Smart Homes – Wall Insulation Standard Technical Details
Effective 3rd December 2014
These standard details should be followed for the Smart Homes project and quotations should confirm
whether this is the case. The Smart Advisor will assume these details are being used, unless otherwise
indicated, when reviewing the quotes and schedules of works submitted for grant approval. Where
there are alternative options given within the standard approach the option used should be stated
clearly on the quote or schedule of works.
General

All installs must be undertaken following the guidance set out in PAS2030 including, but not
limited to, treating all critical junctions. Furthermore, installers must follow the system
designer’s guidelines for working practices as set out in their BBA Certificate and method
statement.

Critical junctions’ technical details must be submitted for approval. This is only required once
per installer, unless a different system is proposed in subsequent installations.
Pipes and Guttering

Where a plastic soil pipe or down pipe can be moved, extended and reconnected it must be and
it is imperative that the system is run behind to avoid a cold bridge. Additional pipework may be
needed, e.g. a swan neck. The only acceptable reason for not extending a plastic pipe is fouling
of the driveway or garage, excessive obscuring or fouling of a window or obscuring a public
highway. Where a plastic pipe cannot be extended for the above reasons installers must install
an appropriate cold bridge solution. Details must be submitted for approval. The system must
not be chamfered into the pipe or extended for no valid reason. A cast iron pipe has limited
ability to be extended and so installers have the option to either replace with new plastic or
install the Thermo Pro Soil Pipe cold bridge solution. An acceptable alternative connection must
be provided whilst the installation is being undertaken to ensure continuity of services.

All gutters and gulleys should be free of debris and in good working order. Any damage must be
repaired or the item replaced. This cost is eligible for Smart Homes funding.
Reveals
All reveals (both window and door) must be insulated. Proposed technical details must be submitted for
approval.. Where a standard insulation product is not suitable due to fouling of the opening, a thinner
aerogel based (or equivalent)cold bridge solution must be used. Hacking off existing plaster / render
(where applicable) may be needed to provide the required room to insulate these reveals.
Please make a note of which of the following approaches you are taking to reveals in the
quote/schedule of works:

Where a window has suitable amount of clearance to allow, we insist that a 20mm grey EPS (or
equivalent) reveal board is installed.

Where a window has clearance to allow for a reveal board but not enough to accommodate the
EPS, we insist that 10mm Aerogel insulation (or equivalent) is installed. Technical details must
be submitted for approval.
For both of the above options, it is imperative that the window is not fouled both in terms of operation
and ventilation. Please consider removing existing render (where applicable) to allow for the above and
to ensure the operation and ventilation is not impeded.

Where a window does not allow enough clearance to install either of the first two options and
there is no existing render to remove, we insist that installers provide an insulated render
solution. Details must be submitted for approval. Whilst the render offers minimal thermal
performance it is imperative that the system is finished in this way. It reduces the potential for
cold bridging at this junction and ensures the system is weather tight.
Please make a note of which of the following approaches you are taking to reveals in the
quote/schedule of works.
Ventilation
All vents must be kept clear and existing flues / vents extended as set out by the HHIC. Additional
ventilation may be required.
Fuel Burning Appliances/Combustion Air Ventilators

All fuel burning appliances require an adequate air supply and a clear flue to operate correctly.
With an appliance in good working order the main product of combustion is carbon dioxide.
Carbon Monoxide is produced though when a flue is blocked or the air supply is impaired. You
cannot see, smell or taste carbon monoxide, but it is an extremely toxic gas. With this in mind it
is absolutely imperative that any existing combustion air ventilator is maintained and extended
through the solid wall system. If there is a fuel burning appliance within the property and there
is no existing combustion air ventilation, then the advice of a qualified Gas Safe engineer should
be sought.
Air Bricks and Ventilators

There are potentially many other air bricks and ventilators on external solid walls and where
these continue to serve a purpose they must obviously be maintained. These may include under
floor air, room ventilators, extract fans and larder/food storage cupboards. Bathroom and
kitchen ventilators should be maintained as should gable end airbricks. Vents serving ducted air
systems must not be compromised. Airbricks may have been sealed by the occupants. The
installer should be mindful of the Building Regulations Part F and the requirement for
permanent low level ventilation in all rooms and should not collude with any action that renders
the property worse than before. They should either open the sealed ventilators or else ensure
that a suitable alternative is provided. Any decision to block off any existing superfluous vents
that have been sealed or decommissioned should be discussed and documented with the
homeowner.
Additional Ventilation

Where condensation already appears to be a problem the homeowner should be advised that
they should consider the installation of a mechanical vent or extract fan in the kitchen or
bathroom, or the retrofitting of trickle vents to windows at window heads and with suitable
adjustable cowls. The cost of these is eligible for grant funding.
Please make a note of any additional ventilation that is being installed within the quote/schedule of
works.
Verge Trims and Eaves
Verge trims must be fitted where a roof line does not overhang the system. These must have a minimum
overhang of 35mm and are to be sealed. Technical details must be submitted for approval.



Where there is 0mm tile overhang you must install flashing on top of the verge trim to ensure
water cannot ingress behind the system.
Where there is some overhang 2mm-100mm use verge trims
Where there is more than 120mm roof overhang no verge trim is required
Where barge boards exist and they sit higher than the internal ceiling height, installers should remove
these and insulate up to the roof line. If barge boards sit higher that the internal ceiling height it is not
essential that this area is insulated but installers must ensure they do not block any existing vents.
Where vents are blocked due to system dimensions, new vents must be created to replicate those lost.
There is additional consideration in this area:

Due to planning restrictions installers may not be permitted to interfere with the barge board if
decorative or adjoining decorative features need to be left in situ.
Regardless of the approach agreed upon, installers must consider the following three key issues
waterproofing, ventilation and cold bridging (in that order).
There is the more expensive option of extending the eaves but this would need to be done by a
professional. A brief note should be issued as part of the quotation, advising the customer that this area
can be extended at additional cost as a good practice option. Technical details must be submitted for
approval.

Flat roofs – as these will vary in structure and integrity verge trim details for these should be
considered on ad hoc basis. Technical details must be submitted for approval.

Where loft insulation is installed, additional roof tile ventilation should be installed as standard,
to mitigate against risk of condensation. Please refer to the CITB Loft Guidance section 5.1.2
and PAS requirements.
Suspended floor insulation

Where suspended floor insulation is installed, additional ventilation bricks should be installed as
standard, if not already present, so as to mitigate against risk of condensation. Air bricks should
be present every 1.8m. Also ensure cross ventilation is maintained/facilitated.
Sills
Sills tend to be stone and concrete in north London or may be tile sills in Edwardian properties. The
agreed standard approach is to oversill and enclose the existing sill with layer of insulation underneath,
with EPS as first option and Aerogel as the second option if room is limited. Installers must ensure they
do not foul the opening and the ventilation of the window, or obstruct window drainage weep holes
(e.g. in uPVC windows).
Undersills are an option, but probably not for these properties
Composite insulated sills should be presented as an option for properties where a stone/concrete sill is
already in place. The original sill would have to be taken out/back with an angle grinder and the new
composite cill instated. Whilst this option will better replicate the original appearance it is considerably
more costly.
Manufacturer’s photos/illustrations to demonstrate the various sill options should be used to present
the options available to the customer.
Base Details
The preferred approach is to treat below DPC, but this is a customer decision. There is no requirement
to treat below the DPC unless the property has been built into the side of a hill (i.e. an elevation sits
lower that the traditional ground level e.g. properties that are 2 story on one elevation and 3 on
another) or properties that have a working, livable basement.
Where this is the scenario or a customer chooses to have below dpc insulated, please note that existing
vents must be kept clear and extended, additional ventilation may be required. Technical details must
be submitted for approval.
The homeowner should be made aware of the enhanced base detail option that will prevent cold
bridging below dpc.
Other

No install can begin until the property has been deemed to be structurally sound and any
remedial work has been undertaken to a satisfactory level. This includes details such as damp,
cracks, damaged / leaking rainwater goods, replacement flues and vents etc. Replacement
rainwater goods, flues and vents may be funded as ancillary works from the Smart Homes grant.

Any issue that would have a negative effect on the finished system must be treated prior to
install. For example, upgrading windows would not be deemed an essential remedial work,
replacing / repairing faulty rainwater goods would.

All work should comply with Building Regulations. Installation must be completed as per the
agreed process and to a satisfactory level. These aspects include detailing around reveals,
meeting party walls and roof lines. Any aspect that falls outside of Building Regulations (for
example the cold bridging solutions) should be discussed with the customer and, if requested by
the customer, must be installed in line with previously approved details.

Any installs found not to be following the process as set out in PAS2030, BBA Certificate, agreed
details and Building Regulations will be halted until rectified.

The homeowner should be advised that scaffold will be provided without an alarm system but
should they require an alarm it can be provided at an additional cost. This should be noted
within the quote/schedule of works.

Where services such as power cables or telephone lines need to be moved please ensure this
work is undertaken by the relevant service provider. Do not try to undertake this work
yourselves.