Thanks for visiting our website. We want to give you some free advices to achieve high building standards for your home.
Please consider the use of counter battens. They ensure a proper roof ventilation and prevent structural damages caused by moisture.
By having counter battens installed, you don´t need a ventilation layer between the breathable membrane and your rafter insulation. That means you can use thicker insulation to get better u-values and less cooling of the insulation through air infiltration.
Weather Tight Sealing
Slates and Roof Tiles are never 100% weather proof. Your breathable membrane protects your roof structure against wind and driving rain.
Please seal (mostly by using special tape) all overlappings, penetrations and connections to roof windows. This is the
only way to make your roof structure completely wind tight.
To prevent damages on the inside of your roof window, the right construction of the reveal is important.
When you build the reveal the wrong way, parts of your window won´t get heated and well ventilated in the winter and you´ll get soon or later condensation and mould in the corners.
DPC on Window Sills
The DPC should be wrapped around the window sill and the window frame goes on top of the DPC. This is the only way to prevent the ingress of dampness through the
concrete of the window sill.
No compromises regarding Window Installation
Your window supplier charges you the full amount for the installation of your windows. Do not accept any messy installation, caused by "speedy installers". Your new
window should last for the next 30 years hence it needs to be fitted in a correct way.
Bear in mind that the window need a proper airtight sealing afterwards. How do you want to achieve this on a window as seen on the photo?
Load bearing capacity of fixings
The photo shows two types of window fixings.
The left strap was originally installed by the window supplier at the bottom of a room-height fixed glazing and will not carry the weight of the window. In coordination with the client, the window got additional appropriate brackets to prevent a drop.
WATER TIGHT FLASHINGS
Lead and DPC are poor sealings
A permanent working water tight sealing can´t be made of lead or DPC.
Please have a look here for the right solutions.
External walls need to be plastered internally
The internal plaster creates an airtight layer for masonry. No matter if you want to use insulated plasterboard or just a hard wall finish in your house, you need
to plaster all external walls of your house on the inside. The blocks are too porous on their own and missing pieces of mortar joints will cause draughts as well.
Don´t forget to seal the joist for the timber ceilings
Many existing houses are struggling with draughts, coming straight out of the ceiling. Please ensure a proper
sealing around all joistes and beams which reach into the cavity. Cavity wall insulation does not create airtightness!
Suspended Ceilings are in need of an air tightness strategy as well
It´s the same principle as shown on the timber ceilings above. The small piece of external wall between the
MF suspended ceiling and the concrete slab need to be plastered as well, to prevent air leakages. Air Tight Paint is a serious alternative to plaster.
The perimeter should get an airtight sealing
When you´re using screed for restoration purposes or underfloor heating, please seal at least the joints to the masonry around the external walls.
The photo beside shows the difference between the sealed external and the plain internal wall. It was taken during an air tight pre-test in a new building.
Cavity walls require an airtight sealing
Whenever cavity walls get access to the inner area of the house, the cavity need an airtight sealing too. Typical building situations are sun rooms and ground level
extensions, having an external gable on the first floor straight above the beginning of the extension. We recommend to close the cavity first by using insulation boards, as used around the doors
and windows. Than you should use an airtight tape or membrane to prevent draughts.
Other trades can dramatically lower the air tight performance
Please take care that following trades do not destroy the air tight installation. Especially electricians and plumbers are great in doing
unexpected modifications afterwards. Please remind that the easiest way for their purpose could end in the worst solution for
the air tight performance of your building.
Attention is needed to prevent air infiltration through sockets
It´s a very common problem in cavity wall houses here in Ireland. Even by having the conduit sealed, there is a noticable draught coming through the sockets and
switches. The reason is the untreated surface in the chasing, where air infiltrates through the block and streams up or down along the conduit. If you want to create a house with low air changes,
you´ll need to seal the chasing before installing the conduits.
HEAT RECOVERY VENTILATION
The right place to install a HRV Units and components
The most efficient system is pointless in case you install the main unit or the manifolds somewhere in your cold roof area. How do you want to achieve good heat
recovery values when these components are not properly protected against cold?
Think ahead regarding duct installation
Please keep in mind that your ducts shouldn´t weaken your insulation. Also please don´t forget that they need a proper airtight sealing afterwards, whereever they
penetrate your vapour control layer.
Especially for retrofit it could make sense to think about a Ductless HRV System.
The layout of your hrv system affects the performance
In general - try to place your hrv unit somewhere in the centre of the house, to keep the runs for the ducts as short as possible. The longer they are, the more resistance they create and the hrv unit has to work harder. Never get terminals connected as seen on the photo. These kinks do lower the performance and increase the noise.
Keep your HRV System protected during the construction stage
Your HRV System is designed to supply you with fresh clean air. Please treat the system carefully during the construction stage and block all plenums and accesses
to prevent the contamination of the system. There´s plenty of dust and dirt involved whilst your house is been built and you do not want to get contact between these particles and your air
Protect your extract ducts
The extract side of your mHRV is running permanently in all of your wet rooms. It´s a fact that not only air will be extracted, because of a significant amount of
dirt and dust in the air.
You´ll see the traces of this pollution clearly around your extract vents and inside of the extract ducts in a certain while. The solution to prevent this situation is already available - you just need to get in contact with us.
Prevent uninsulated parts at your building envelope
The plan was, to use beads for pumping the cavity walls and spray foam for the roof area. Unfortunately there is a triangle which will not be covered by the
proposed insulation materials. The cavity needs to get blocked on top for fire safety reasons and the spray foam can not applied into the eve area because of lack of access and missing counter
battens under the slates. The actual detail will definitely cause a cold spot on the inner leaf which will end in dampness and mould.
Insulated slabs on perimeter walls
Please consider the following facts before installing an insulated slabs on a perimeter wall:
1. Risk of interstitial condensation
2. Lowering of thermal mass
3. Cold bridging through metal mushroom fixings
If you want to go ahead with this insulation strategy, please make sure you have the wall covered with an air tight layer (plaster or air tight paint) prior to the installation of the slabs.
Get your cables installed in a neat and clean way.
It could happen some day that you might need to detect a faulty cable.
Especially when the cables have been laid up and down above your metal frame ceiling, you´re increasing the risk of damaging the sheating around the cable.
This happens because there´s a movement all the time in the structure and the cable can rub on the metal.
Is this lighting strategy still up-to-date?
Recess lights do have advantages but disadvantages too. Every recess light is costing you a good amount of money during the installation process. It creates weak spots for the air tightness and insulation. The beam angle is pretty low in comparison to pendants or ceiling mounted lights, which leads to a certain quantity to brighten the room. But the more recess lights you have installed and running, the more you´ll be affected by shadowing.
Locating external units of air-to-water heat pumps
It´s not the best idea to install the external unit of an air-to-water system facing windwards. If you have not other option, consider the installation of a barrier
in an appropriate distance, to prevent that the wind affects the performance of your heat pump.
Do not place the unit to close to your house as well, otherwise you´re risking damp walls in the winter.
Are you looking for bespoke advices for your house?
Why not consider a consultation to make your house home?