Polypipe Under Floor Heating Systems Technical Installation Manual
TIG1 JULY 2009
EFFECTIVE: 1ST JULY 2009
Under Floor Heating Systems
Technical Installation Guide
July 2009
Technical Installation Guide
Under Floor Heating Systems
Polypipe Building Products
Broomhouse Lane
Edlington
Doncaster DN12 1ES
Tel: 01709 770 000
Fax: 01709 770 001
2410 London Road
Mount Vernon
Glasgow G32 8XZ
Tel: 0141 778 8822
Fax: 0141 778 2703
Dromore Road
Lurgan, Craigavon
Co. Armagh BT66 7HL
Tel: 028 38 881270
Fax: 028 38 882344
www.polypipe.com
Under oor heating systems trade website: www.ufch.com
Under oor heating systems consumer website: www.freeyourwalls.com
Polypipe oor heating products, excluding manifolds and control products, are covered by a 50 year guarantee*, which protects against
defects in materials or manufacture of the heating system from date of purchase. This guarantee only applies if the system is installed
in accordance with the manufacturer’s recommendations contained within the Technical Installation Guide (the latest version of which
can be found at www.ufch.com), and is used in a normal domestic operation. This document should be read in conjunction with all other
documentation supplied with Polypipe products.
If you have any queries please contact our Technical Department on 01709 770000.
*Full terms and conditions for Polypipe heating products 50 Year Guarantee are available at www.ufch.com
CONTENTS
How to use this guide ............................................................................................................03
INTRODUCTION
About Polypipe ......................................................................................................................04
An overview of under oor heating systems ...........................................................................06
Selecting the right Polypipe under oor heating system ..........................................................07
System selection ....................................................................................................................08
Design service ........................................................................................................................09
Guide to oor coverings for under oor heating systems ........................................................10
INSTALLING THE SYSTEM
Solid Floor ..............................................................................................................................12
Floating Floor .........................................................................................................................16
Suspended Floor ....................................................................................................................18
Modular Heating Panel ..........................................................................................................22
Overlay™ ...............................................................................................................................28
Overlay™ Lite ........................................................................................................................36
CONNECTING & CONTROLLING THE SYSTEM
Connecting to heat source .....................................................................................................38
Manifolds ..............................................................................................................................39
Water temperature controls ...................................................................................................40
Room temperature controls ...................................................................................................41
Single room applications ........................................................................................................44
System commissioning ...........................................................................................................46
TECHNICAL DATA
Heat output tables .................................................................................................................48
General system information ...................................................................................................49
FAULT FINDING CHARTS
Hydraulic fault nding chart ...................................................................................................50
Electrical fault nding chart (master connecting box) ..............................................................51
STANDARDS
Accreditations, standards and guarantees ..............................................................................52
FORMS
1-2-3 Product selection form ..................................................................................................53
Design enquiry form ..............................................................................................................54
LITERATURE
Other information and literature ............................................................................................55
02 03
HOW TO USE THIS GUIDE
Important notice:
This publication is provided as a comprehensive guide on how to install Polypipe
under floor heating systems. It is an important document as we cannot accept any
liability, or honour any guarantee, for products and systems that have not been
installed in accordance with our published instructions.
From time to time our installation advice may be updated
at which time previous printed copies will become out of date.
The latest version of our installation advice, including a downloadable
version of the current Technical Installation Guide, can be found
at our trade website, www.ufch.com
Selecting the right system
This guide is intended for competent trained plumbing and
heating installers and we assume that you will have already
specied your system of choice before consulting this publication
for installation advice. Basic information on selecting the right
system is provided in this guide. For more detailed guidance
refer to our Design & Specication Guide or visit our trade
website at www.ufch.com or consumer website at
www.freeyourwalls.com
Navigating the Technical
Installation Guide
Having read the general introductory sections at the front
of the guide, ensure that you have selected the correct system
for your oor type and project. Read the guide to oor coverings
to ensure that your system is compatible with your oor type.
Next, choose your selected under oor heating system type from
the section “Installing the system” and follow the step by step
instructions. Everything should be straightforward but remember
that the Polypipe Technical Support team is always ready to help
answer any questions you may have.
Whichever Polypipe under oor heating system you are installing
you will need to refer to the information provided in the section
“Connecting and controlling the system”. This section provides
all you need to know about manifolds and controls, connecting
your system to an appropriate heat source and commissioning
the system.
Technical data
Towards the back of this guide you will nd technical data such
as heat output tables, pipe data and general system information
as well as useful forms to use with our Product Selector
and System Design Service.
Additional information
Should you have any questions at any time, or require any
kind of technical support call our Technical Support team
on 01709 770000.
Online assistance is available at www.ufch.com, our comprehensive
website for installers, developers and merchants. As well as
information on technical advice and product benets, you can
nd useful case studies and details of Polypipe stockists.
Video instructions on under oor heating installation are also
available to view.
04 05
ABOUT POLYPIPE UNDER FLOOR HEATING
Easy installation
Polypipe under oor heating systems have been designed with
ease of installation in mind. Innovative product designs ensure
minimal disruption to existing heating and electrical supplies
during installation. As our systems are compatible with standard
central heating boilers, connectivity is also streamlined. Polypipe
under oor heating systems can be installed up to 20% quicker
than radiators.
Polypipe under oor heating systems are installed in one stage,
eliminating the need for a time consuming second x. Under oor
heating components are much easier to manoeuvre on site than
large, bulky radiators; reducing handling issues and potential
damage. Unlike radiators, there is also very little theft value
during installation.
Details of each type of Polypipe under oor heating system can
be found on page 6.
Maintenance free
Once installed, a Polypipe under oor heating system is virtually
maintenance free. There are no joints in the pipe work within the
ooring, signicantly reducing the possibility of leaks. Polypipe
under oor heating products are subjected to rigorous testing
and meet a number of exacting standards, full details of which
can be found on page 52. All our manufacturing processes are
monitored and controlled in accordance with the international
quality standard BS EN ISO 9002.
Choosing under oor heating also eliminates a number of
general maintenance and decoration requirements, normally
associated with radiators, such as painting the radiator or
removing it to paint the wall.
Demonstrating the utmost condence in product performance,
and providing our customers with peace of mind, Polypipe under
oor heating systems are covered by the Polypipe 50 year
guarantee (full details can be found at www.ufch.com).
Easy to control
Polypipe manufactures a range of water and room temperature
control solutions, allowing you to source a complete, integrated
system from a single supplier. The range includes a number of
control products, with options to suit a variety of lifestyle
patterns, and the abilities to control different rooms independently.
Full details of Polypipe control products can be found on pages
40 to 43.
Flexible approach
Polypipe under oor heating systems use the exibility of polybutylene
pipe to provide a solution for all house and room types. We also
have a range of unique and innovative products, including the
Zonal Regulation Unit (ZRU) which is an excellent enabler allowing
under oor heating systems to be incorporated into single rooms
or refurbishment projects with minimal disruption to existing
heating and electrical supplies.
For more information on our single room applications see pages
44 and 45.
Excellent service
At Polypipe we understand that selecting the right solution for
each application involves detailed consideration. This is why we
offer extensive customer service support, including free system
design and full technical support if any problems arise. We want
to ensure that your installation runs smoothly from the beginning
and our technical support staff can assist you with any questions
you might have.
During installation we offer:
• Pre-project training at one of our training centres
• Pre-project training by distance learning
• On-site assistance
We also provide an extensive back up service:
• Technical representation available to discuss systems in general
and particular projects
• www.ufch.com
• Technical Installation CD
• Specialist Technical Hotline on 01709 770000
Energy efficient
Under oor heating systems can be more economical to run
than radiator based systems. As they demand a low temperature
rise output from the boiler, they are ideally suited to achieving
maximum economy from a condensing boiler or heat pump.
However, they are just as efcient with higher temperature heat
sources, for example solar and solid fuel, where the correct water
temperature can be set at the point of distribution.
Polypipe is one of Europe’s largest manufacturers of specialist plastic plumbing,
heating, waste and drainage products.
Our market leading under floor heating product range has been continuously
developed and improved with frequent innovative additions, the latest of which
are Modular Heating Panels (MHP) - a revolutionary solution for suspended floor
applications - and Overlay™ Lite, a lightweight floor panel to complement our
innovative over floor heating range.
Polypipe is a member of the Underfloor Heating Manufacturers’ Association (UHMA),
who set and enforce standards for materials, design and installation of under floor
heating systems - standards that we embrace within every aspect of our range.
Polypipe under oor heating systems have been designed with
speciers, installers and users in mind.
Our systems combine ease of installation with reliable long-term
performance, and we hold a range of stock ready for prompt
dispatch. Unique to the Polypipe service proposition is our
room and house packs concept. Recognising that under oor
heating systems are difcult to specify using individual components,
we created a range of over 300 pre-set combinations that can
be ordered as complete kits. By simply specifying key variables
such as oor type, room size, control and circuit data the right
pack can be specied in minutes. It’s as easy as .
We have even created a unique online product selection tool.
Following recent innovative product introductions, we have
categorised our range into 3 groups in order to make selecting
even more instinctive:
With a long established reputation for product quality and
value, backed by our strict trade-only distribution policy,
Polypipe has become the clear leader in the under oor
heating category. Recent innovations ensure the Polypipe
range is the widest available from a single manufacturer,
including traditional under oor heating systems for every
oor type as well as the innovative MHP and Overlay™ products.
Polypipe under oor heating systems are ideal for every
application, including new build, self build, renovation and
home improvement projects. Whole house, single oor and
single room projects are equally catered for in our extensive
product offering. Whatever job you are undertaking, Polypipe
has the product to suit.
Polypipe is a recognised and respected brand, and is well
established as the system of choice for domestic homes by
many installers. All Polypipe under oor heating systems are
supplied as a complete system, and require no additional
components for installation. Polypipe under oor heating
systems are rigorously tested, and comply with (or exceed) all
relevant UK standards. We use an integrated exible plumbing
system, incorporating polybutylene pipes and a range of pusht ttings. The systems are also designed for use with copper
pipes, allowing the integration of rigid pipes when necessary.
OVERLAY™
LITE
OVERLAY™
SOLID
FLOOR
FLOATING
FLOOR
06 07
AN OVERVIEW OF UNDER FLOOR
HEATING SYSTEMS
SELECTING THE RIGHT POLYPIPE
UNDER FLOOR HEATING SYSTEM
Polypipe has the widest available range of under floor heating systems, with a
product available for every conceivable floor type or residential heating project.
With Polypipe, under floor heating is not restricted to new build developments or
self build projects. Our unique Overlay™ product is particularly well suited to single
room projects such as kitchens, bathrooms, conservatories, extensions and loft
conversions. Polypipe Modular Heating Panels (MHP) were developed to provide an
innovative and practical solution to installing under floor heating into upper floors.
The notes below provide a brief overview of the methodologies
employed to install under oor heating systems for various oor
types. Refer to the overview on the page opposite. Full installation
instructions for each oor type can be found in the section titled
‘Installing the system’ on pages 12 to 36.
Solid Floor
Polypipe under oor heating can be permanently built into solid
concrete or screeded oors. As required by current Building
Regulations, insulation is built into the oor directly beneath the
unique Polypipe lightweight plastic oor panel. The heating pipe
is simply slotted into the panel and then permanently covered by
the screed. Suitable for all oor coverings, solid oor systems can
incorporate 15mm or 18mm pipe.
The oor panels form a simple grid for the quickest possible
pipe laying and provide a precise guide to achieve the minimum
bending radius. Panel
castellations are set at exact centres and
hold the pipe against movement when screeding. The oor panel
holds the pipe above the insulation allowing full screed surround.
Optimum screed depth is 65mm from the panel base, i.e. 40mm
from the pipe top. Insulation below and at the edges of the oor
screed is required by Building Regulations. Edge insulation also
acts as an expansion joint.
Floating Floor
When installed in oating oors, Polyplumb pipe is simply pressed
in to the pre-formed heat spreader plate, which sits in grooves
within the oating oor insulation panel. The oating oor
system is then covered with 18mm chipboard sheeting. Suitable
for all oor covering, oating oor systems can incorporate
15mm or 18mm pipe.
Suspended Floor
For installations in suspended oors, Polypipe under oor heating
uses double heat spreader plates. Alternatively, pipes can be laid
on top of insulation between joists. Standard tongue and groove
oorboards are laid on top of the system. Suspended double heat
spreader plate systems use 15mm pipe.
MHP (Modular Heating Panels)
Modular Heating Panels offer a revolutionary new way to solve
the issue of installing under oor heating into upper oors. MHP
is available in two widths and two lengths to t all standard joist
spacings. All components and circuitry is pre-congured into
the panels which are simply installed between the joists, linked
together and connected to the manifold.
Overlay™
Overlay™ allows under oor heating to be installed into existing
spaces quickly, easily and practically. The unique system is
supplied with a choice of patented low prole panels to suit all
types of oor coverings. The Overlay™ system is laid over existing
solid or timber oors.
Under floor heating systems
Product selection: Typical applications and features
New build Existing floor
SUSPENDED
FLOOR
Under floor
All floor
coverings
High mass
system
Typical ground
floor or beam
and block
construction
All floor
covering
except natural
wood/thick
laminates
Lightweight
construction
No wet trades
required
Lightweight
floor coverings
Larger areas
Multiple rooms
Tiles or
natural wood
Wet areas
Over floor
MODULAR
HEATING
PANEL
All floor
covering
Fit from above
Traditional
joists
Traditional
heat source
All floor
coverings
Fit from
above/below
Traditional
or engineered
joists
Traditional or
renewable heat
sources
SUSPENDED
FLOOR
08 09
SYSTEM SELECTION
Our comprehensive system
design service includes:
• System design, including heat loss calculations
for residential applications
• Circuit lengths
• Circuit pressure losses and velocities
• Flow rate settings per circuit
• Full product material specication
Installation service
• Pre-project training at training centre
• Pre-project training by distance learning
• On-site assistance if required during project installation
Backup service
• Technical representation available to discuss systems
in general and particular projects
• Web-site and information on CD
• Specialist Technical Hotline on 01709 770000
Polypipe has removed the mystique from specifying the correct under floor
heating solution for a given project and the need to calculate all of the individual
components required. Our unique Product Selector, which is available
on page 53 or online at www.ufch.com, uses a simple 3 step process to calculate
your requirements using basic project data that you provide. The system includes
details of over 300 pre-configured system kits that contain all of the parts and
components you need. Once you have determined the correct pack for your
project it can be ordered under a single item code via your merchant.
DESIGN SERVICE
For projects that fall outside the scope of the room packs or house packs,
Polypipe offers a fully bespoke system design service. To utilise this facility, simply
complete the enquiry form on page 54, or at www.ufch.com, and submit your
drawings to Polypipe. You will then receive a complete design and component
list for the project.
To use the Polypipe Product Selector you rst decide whether
the project is a single room, a whole house solution, or requires
a bespoke design. You then simply input data for each room,
providing oor type, room size, and control zones to calculate
the required pack.
All packs have a single order code and include all the necessary
ooring materials, pipe, distribution (manifolds, ZRU, etc.),
water temperature and room temperature controls.
To select the appropriate solution, choose from the
following options:
Room Packs
Room packs are designed for single room applications: i.e. kitchens,
bathrooms, conservatories, loft conversions and extensions.
This range of under oor heating packs contain all the ooring
and control equipment required for a single project, in solid oor,
our traditional Overlay™ and our NEW Overlay™ Lite systems.
All room packs have a maximum heat output of 100W/m
2
.
House Packs
House packs provide you with a quick and easy way to select and
order from our range of under oor heating products, without the
need to submit a design. The packs are designed for solid, oating
or suspended (double heat spreader plate) projects.
Packs can be applied to all new build or renovation properties that
fall into the following criteria:
• Rooms requiring up to 70W/m
2
• Properties built to current Building Regulations
• Projects where the manifold can be positioned within 6m
of the room entrance
Design services
For projects that fall outside the scope of the room packs
or house packs, Polypipe offers a fully bespoke system design
service. To utilise this facility, simply complete the enquiry form
on page 54, or at www.ufch.com, and submit your drawings
to Polypipe. You will then receive a complete design and
component list for the project.
Modular Heating Panels
Our revolutionary new MHP panels, designed to make under
oor heating easier to install between ceiling joists for upper
oor suspended oor applications, have their own product
selector, which is also available online at www.ufch.com
10 11
GUIDE TO FLOOR COVERINGS
FOR UNDER FLOOR HEATING SYSTEMS
Under floor heating systems will work efficiently with any floor covering, as long as it
is well insulated underneath. However, each covering has different thermal conduction
properties, and harder surfaces offer better conductivity and, therefore, better heat
output rates. The following notes provide some guidance on each type of covering.
Vinyl
Suitable for all Polypipe under oor heating systems:
Sheet vinyl is sensitive to long term exposure to heat. There are
two categories of vinyl; one is limited to constant temperatures
of around 26°C and the other to 30°C. Check the oor surface
temperature indicated by your vinyl supplier for compatibility
with under oor heating. If unsure contact the Polypipe hotline
or the vinyl oor manufacturer.
Laminate
Suitable for all Polypipe under oor heating systems:
Laminate ooring should be laid on roll type oor leveller,
rather than the rigid panel type. Movement that occurs must
be accommodated by an expansion gap around the oor deck.
Timber
Suitable for Polypipe solid oor and suspended oor systems:
Concerns regarding the effect of heat on a timber oor are
misplaced. The more important issue is the oor moisture
content. Timber oors should be laid at a moisture content
of 10-11%, which when heated will reduce to 8-9%, and cause
only a very small amount of shrinkage. The oor will re-absorb
some moisture when the heating is not operating and the
moisture content will increase to 12-13%. Further details
on installing timber oors over Polypipe under oor heating
systems can be found on page 15.
Carpet and underlay
Suitable for all Polypipe under oor heating systems:
The nature and thickness of the carpet underlay is fundamental
in determining good heat transfer. The most popular underlay
type is sponge with a wafe pattern moulded into the underside.
These allow good heat transfer. Felt and rubber crumb underlay
should be avoided. These products can seriously reduce the
effectiveness of an under oor heating system, as they insulate
the oor surface and prevent heat transfer.
The TOG value of carpet and underlay should be available from
the respective manufacturer. For optimal system performance
choose an underlay with a maximum TOG value of approximately
0.5. The maximum TOG value of carpet should be approximately
1.0 to 1.5.
Stone and ceramic tiles,
marble or flagstones
Suitable for all Polypipe under oor heating systems:
These types of oor nishes are usually cold underfoot.
However, with oor heating they are transformed into warm
comfortable surfaces. Each of these nishes is essentially
brittle and it is imperative that the design of the supporting
oor structure is stable and rigid to prevent cracking.
It is recommended that exible adhesives and grout be used.
Pre-installation requirements
The sub oor must be swept clean and be free from mortar residues.
Installation
Fitting Insulation
Step 1:
In accordance with Part ‘L’ of the current Building Regulations,
a suitable layer of insulation material should be included within
the oor construction. It is the responsibility of the Architect or
Builder to ensure compliance. However, in all instances insulation
must be installed beneath the under oor heating system in order
to ensure that any downward heat loss does not exceed 10W/m
2
,
in accordance with BS EN 1264.
Fitting the edge insulation strips
Step 2:
Using edge insulation strip allows the free expansion of the oor
screed. The insulation strip should be installed around all perimeter
walls and xed constructions such as columns, steps and access doors.
Edge insulation strip is bent at 90° near to the base to form
a double sided self-adhesive strip which bonds the oor plates
to the oor insulation. Edge insulation strip should be tted in
addition to perimeter insulation required by Building Regulations.
Fitting the floor panels
Step 3:
The oor panels are laid over the pre-installed insulation and
should be overlapped at the edges.
NOTE: The ½ castellation should overlap the ¾ castellation. The rst
panel should be laid with the ½ castellation edge against the wall.
Panels can be cut by simply using a saw or snips or it can
be overlapped to the nearest castellation t.
Floor panels should not be used at the base of the manifold
as pipes need to be closer together than the oor panels allow.
Pipes around this area should be secured using pipe clips which can
also be used intermittently to secure the clip plate to the insulation.
When a pumped (liquid) screed is to be used it is essential that all of
the panel joints are made correctly and that no panels are allowed to
simply ‘butt-up’ as this may allow the screed to penetrate below the
under oor heating system and cause the panels to rise up. Similarly
the panels should be rmly secured around the perimeter of the room
using staples so as to prevent possible risk of the panels lifting.
Preparing the pipe
Step 4:
You will need to remove the coil from the bag, leaving the shrink
wrap on, uncoiling from centre of the coil.
Laying the pipe
Step 5:
Once you have completed laying the solid oor panels the pipe
can be tted starting at the manifold position in line with the
pre-designed centres. 15mm and 18mm pipe can be laid
at 100mm or 200mm centres as required, 18mm pipe can also
be laid at 300mm centres.
The minimum bend radius is achieved by encircling two
castellations for a 90° bend or three castellations for a 180° bend
(see diagrams on next page).
12 13
SOLID FLOOR
Key design and installation information
Material requirements (approx)
Maximum heat output Approx. 100W/m
2
Recommended design ow temp 50°C
Maximum circuit length 100m (15mm pipe)
120m (18mm pipe)
Maximum coverage per circuit 12m2 at 100mm centres
22m2 at 200mm centres
30m2 at 300mm centres*
*(18mm pipe only)
Pipe 8.2m/m
2
at 100mm centres
4.5m/m2 at 200mm centres
3.3m/m2 at 300mm spacing*
*(18mm pipe only)
Floor plate usage 1 plate/m2 allowing
for cutting
(Actual 1·2m2/plate)
Edging insulation strip 1.1m/m
2
Conduit pipe 2m/circuit
Polypipe under floor heating in solid or screeded floors incorporates the unique
Polypipe screeded floor panel. The lightweight plastic floor panels nest
for easy storage and carrying.
Polypipe has the perfect solution for installing under oor
heating into solid or screeded oors. Utilising our unique
lightweight plastic oor panels, which are quick and easy to
cut to size, it is possible to t Polypipe under oor heating into
any shaped room.
Polypipe solid oor panels form a simple grid to ensure the
fastest possible pipe laying and also provide a precise guide
for the pipe, ensuring that the minimum pipe bending
radius is achieved.
The panels are laid above pre-installed insulation and the
system includes edging insulation strip to ensure maximum
performance and efciency.
Polypipe under oor heating systems can be used with
the following solid oor constructions:
• Sand & cement screed (4:1 mix)
• Pumped screed systems (anhydrite, etc)
• Fine or heavy concrete
• Polymer modied screeds
Step 6:
Circuits being laid at 100mm or 200mm centres must be laid in a spiral
conguration. The rst loop of pipe should be laid around the perimeter
of the area to be covered by that circuit. The next loop of this circuit
should be laid either 200mm from the rst loop of pipe for 100mm
centres or 400mm from the rst loop of pipe for 200mm centres.
Step 7:
Continue to loop the pipe into the centre of the panels leaving
enough space to form a double return (‘S’ shape in the centre
of the loop).
Step 8:
Now work back out from the centre by lling the space between the
inwardly spiralling loop of the primary circuit ensuring the pipe is laid
at the correct spacing centres.
18mm pipe installation formation
Where 300mm centre spacing is require (18mm pipe systems only)
a meander pattern can be used. The pipe simply crosses the room
from one side to the other encapsulating 3 castellations at each
return bend.
Conduit pipe
A 400mm length of conduit pipe should be tted over the under oor
heating pipe in any situation where damage may be caused to the
pipe i.e. where the pipe passes through internal walls or doorways,
where the pipe emerges through the oor up to the manifold
or where the pipe passes through either an expansion or day joint.
Preformed long radius bends can also be used to provide a neater
solution if required.
A section of conduit pipe 400mm long should be tted around the
heating pipe where the pipe passes through the edge insulation strip,
e.g. room to room, or through expansion joints within the oor.
Conduit pipe should also be used where the pipe leaves the oor
adjacent to the manifold. This can be threaded down the pipe
after the pipework has been installed.
14 15
Expansion joint
BS EN 1264-4 recommends that an expansion joint is constructed
in stone and ceramic nished screeds for every 40m
2
of oor area
at a maximum length of 8m and an aspect ratio of 2:1.
An expansion joint is also required in long narrow areas such
as corridors, etc.
The image below shows a typical arrangement where the pipes
pass through either an expansion or a day joint. A strip of edge
insulation is used to provide the expansion capacity.
For further information regarding oor screeding requirements
for under oor heating systems please refer to BS8204-1 or the
BISRIA Guide: Screeds with Under Floor Heating.
Testing
Step 9:
Once the pipes circuits have been installed and pressure tested the
screed cover can be applied. Care should be taken to ensure that
the screed is tightly compacted around the pipe to ensure that no
voids are present. The system should remain under pressure (6 bar)
in order to prevent the risk of any damage being caused to the
walls of the pipe whilst the screed is being applied.
Laying the screed
Step 10:
The overall quality and thickness of a sand and cement screed
should meet the requirements of BS8204-1 which stipulates that
in domestic or light commercial applications a minimum thickness
of 65mm should be used. The thickness of alternative coverings,
such as anhydrite or polymer modied screeds, may differ depending
on construction requirements. This information should therefore
be provided by the specialist screed manufacturer/supplier.
After the screed has been laid the oor should be covered with
a membrane to retard the drying out process, particularly in warm
weather. The oor should be allowed to cure and dry naturally until
full strength is reached in accordance with relevant British Standards
and manufacturers’ instructions (approx 30 days for sand and
cement and concrete oors). Under no circumstances should the
under oor heating system be used to articially dry/cure the screed
as this could cause the screed to crack and seriously undermine
the integrity of the oor construction. Once the screed has fully
cured the under oor heating system can be switched on and the
manifold ow temperature slowly increased up to the calculated
design temperature.
Finishing
Timber floors
Many people are concerned by the effect of heat on a timber
oor, but this concern is misplaced. The important factor is the
oor moisture content.
Timber oors can be laid directly over the screed at a moisture
content of 10-11% which during the heating season will reduce
to 8-9% and may cause a small amount shrinkage.
The oor will re-absorb some moisture when the heating is not
operating and the moisture content will increase to 12-13%.
Application of timber floors over solid floor systems
Where solid oak ooring is to be laid on a solid oor, joists can
be tted at 1m centres to provide a xing point for the boards.
Insulation, solid oor panels and pipe can be laid between
the joists and screed laid level with the top of the joists
(see diagram below).
Individual circuits of pipe are then laid between each set of joists
with care being taken to ensure the screed is completely dry prior
to tting the solid oak covering (see diagram).
90° 180°
Screed
Timber floor covering
Solid floor plate
Joist at 1m spacings
Pipe
Conduit
Insulation
Sub floor
Pre-installation requirements
The sub oor must be swept clean and be free from mortar residues.
Installation
Laying the floating floor panels
Step 1:
Lay the 1200 x 1200 x 50mm oating oor panels directly over
the entire oor area to be heated, ensuring the panel grooves are
aligned. The panels can be cut to t where necessary.
A void in the insulation is often retained around the edge of the
room to allow for distribution pipes to be laid from the room
to the manifold.
Laying the spreader plates
Step 2:
Single heat spreader plates that have pre-formed grooves at
300mm centres need to be laid on top of the oating oor panels.
These plates ensure an even spread of heat across the oor area
and hold the pipe rmly within place in the oating oor panel.
Laying the pipe
Step 3:
Once you have completed laying the oating oor panels and heat
spreader plates the pipe can be tted into the pre-formed grooves of
the heat spreader plate. Start at the manifold position and use the
grooves in the oating oor panel to loop round the entire room.
The maximum circuit length is 80m using 15mm pipe or 100m
using 18mm pipe. Pipe should be laid in the pattern shown below.
NOTE: Areas of potential high point loading, e.g. under heavy
furniture kitchen units and appliances, will require additional oor
support. Timber battens (50mm x 50mm) should be positioned
between the oating oor panels and notched to allow the passage
of pipes.
Testing
Step 4:
Once the pipe circuits have been installed and connected to the
manifold the system should be pressure tested to 6 bar for a
minimum of 1 hour before the timber oor covering is laid. It is
recommended that the system remains under pressure whilst the
ooring is laid.
Finishing
The room can then be nished by tting 18mm or 22mm tongue and
groove sheets of chipboard, glued on the edge, over the oating oor
system. Mark the position of the pipe where door thresholds or carpet
strip are to be installed.
When laying a ceramic or stone oor covering ensure that any
deection in the oor is minimised. It is recommended that a slip mat
or uncoupling membrane is used rather than a second layer of wood.
The Polypipe floating floor system is designed for use in applications where a solid
floor installation is not suitable due to structural weight limitations or where a
‘dry build’ floor option is required. Suitable for use in either new build or existing
properties, the floating floor panels can be installed directly on top of both solid
and timber floors.
The 50mm thick high density polystyrene panels have a
thermal value of 0.036W/mK and can be used to enhance
the thermal insulation requirement of the oor structure as
required under current Building Regulations. However, care
should be taken when installing oating oor panels on top
of a primary insulation layer to ensure that excessive deection
does not occur in the nal oor construction.
It is therefore recommended that any other insulation
materials used below the oating oor panels are of a high
density construction (100kN/m
2
@ 10% compression min).
16 17
FLOATING FLOOR
Key design and installation information
Pipe 3.1m/m2 at 300mm centres
Floating oor panel 1 panel/1.4m
2
Single spreader plate 3 plates/m
2
Material requirements (approx)
Maximum heat output Approx. 70W/m
2
Recommended design ow temp 60°C
Maximum circuit length 80m (15mm pipe)
100m (18mm pipe)
Maximum coverage per circuit 25.8m2 at 300mm centres
(15mm pipe)
30m2 at 300mm centres
(18mm pipe)
Polyplumb
barrier pipe
Single heat
spreader plate
Insulated floating
floor panel
Loading...