Free Advice to make your home more efficient

Thanks for visiting our website. We want to give you some free advice to achieve high building standards for your home.


Counter Battens
Counter Battens

Counter Battens


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.

Taping of breather membranes
How to create a wind-tight roof ?

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.

Roof Window Installation
It´s important to have the right reveal structure for roof windows

Roof Windows


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.



Perfect Installation of DPC for Window Sills
Perfect prepared window sill

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.

Another great example for MJ window installation
Typical window installation

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?

Appropriate brackets instead of basic straps to hold a window
Basic inappropriate strap to the left, functional bracket on the right

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.


Archaic water-tight sealing made in Kerry
How do you want to ensure a water-tight sealing by using lead?

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.


Only plastered walls are airtight
Perfect preparation for the installation of insulated plasterboards

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.

Plaster around joists for timber ceilings creates airtightness
Whereever ceiling joists reach into the cavity, they have to sealed

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!

How to ensure airtightness above mf ceilings
MF Ceilings need attention regarding 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.

Proof of necessity for perimeter air tight sealing
Perimeter Sealing on external walls

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.

Airtight sealing for cavity walls
The most forgotten seailing regarding airtightness

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.

All trades at the building site should take care regarding air tightness
Sometimes they don´t know what they do

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.

Chasings on exterior walls need to be sealed air tight
Air Tight Sealing of chasings

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.


the most inappropriate HRV unit installation
When every filter change turns into nightmare...

The right place to install a HRV Units and components


Keep in mind that your hrv unit requires constant access for changing the filters and further maintenance work. 

Placing the unit in a cold surrounding (cold attic) will increase the risk of condensation and decreases the efficiency.

HRV Ducts lowering insulation values
HRV Ducts are not made for insulation purposes.

Think ahead regarding duct installation


Try to keep all ducts within the thermal building envelope. Also, please don´t forget that they need a proper air tight sealing, wherever they penetrate your air tight & vapour control layer.

Especially for retrofit it could make sense to think about a Ductless HRV System.

Flexible ducts should be kept short and without kinks
Please do not install the ducts as seen on the photo

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.

Prevent to get your HRV ducts contaminated with dust and dirt during the building stage
Supply of germs and bacterias included

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 supply.

There is a high risk of contamination for every extract duct of mHRV
Is this looking healthy???

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.


The 200mm wide cavity is worthless in the top area where the wall plate is.
The 200mm wide cavity is worthless in the top area where the wall plate is.

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.

bad detail of finishing external wall insulation at ground level
wrong detail - the plinth insulation has been left open at the bottom

External wall insulation requires real experts


Do not watch out for grants - select real professionals for external insulation instead. An external wall insulation system is the perfect insulation for new and existing buildings but the performance depends to the experience of the installers. Attention is needed to details and never ever put on the render and finishing coat in the winter!

insulated slab on perimeter wall
typical detail of perimeter wall insulation with an insulated slab

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.


The difference between a poor and a good installation of cables
Which installation would you prefer?

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 the installation of recess lights still up-to-date?
We counted a total of 28 recess lights on the photo

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.

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