We get many queries from builders, tradespeople and homeowners who want to know more about airtightness and the tests around Passivhaus and eco-builds. To help out, here we’ve formed a list of the most frequently asked questions (FAQs) around airtightness, and our answers to them.

  • What is airtightness?

    Airtightness is a term which originated from the Passive House building movement and is used in eco construction for describing the layer which is responsible for making a building airtight. This could refer to materials such as airtightness membranes, tapes, boards or coatings.

  • What is wind tightness?

    As the name suggests, this is a layer which is responsible for keeping the wind out of the structure. If wind is able to blow into the insulation layer, then this can result in precious heat being lost more quickly. The wind tightness layer could be in the form of a breathable membrane, which has all the joints taped to ensure good wind tightness.

  • Why is airtightness important?

    Energy losses through uncontrolled drafts can be responsible for a significant amount of a building’s heat loss. The best way to eliminate unwanted draughts is by having a good airtightness strategy. Making a building as airtight as possible can reduce the heating costs or, as with a Certified Passive House, remove the need for a heating system altogether.

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  • Can I make my building or house too airtight?

    No, don’t worry! It is not possible to make a hermetically sealed building, so the best strategy is to make it as airtight as you can.

  • If I am only renovating a bit of my house, what do I do for airtightness?

    While you may only be renovating a small section of your house or building you can still come up with a whole strategy for how you can make it more airtight and then you can implement further improvements to the rest of the house over time. Most importantly, airtightness works have to be done at a specific stage of the building project, otherwise you can miss the opportunity. It is very difficult and costly to rectify airtightness further down the line.

  • Should I still be worried about airtightness if I am not building a Passive House?

    Yes! In a Passive House there is a requirement to achieve a certain air tightness level (0.6 ACH at 50 pascals pressure), and obviously the more airtight the building the better, but we mustn’t forget the motto ‘Built Tight, Ventilate Right’. This means that even though airtightness is very important, it is also very important to have a robust ventilation strategy, and you need to look at your building holistically.

  • Do I need to get an air pressure test done?

    We would advise most people who are undertaking a renovation or new build to get an air pressure test done midway through the project. This would be when all the windows and doors have been installed and airtightness works are complete but haven’t been covered up yet. An air pressure test usually costs between £200-£300. By doing an air pressure test, you can easily find out if there are any holes in the airtightness layer, and these can be easily remedied before they get covered up (after which little can be done to fix them).

  • Why do some airtightness tapes cost more than others?

    Like any product on the market there is a whole range of options available, and we do believe you get what you pay for. That’s why we have partnered with Pro Clima to stock their entire range. They are one of the leading Passive House airtightness suppliers and their tapes and membranes have been tested to last the whole life of the building.

    Air tightness really isn’t something to scrimp on – you need to get it right the first time. We have been using Pro Clima tapes in our own building projects for well over a decade, and we use them because they are the best.

  • Who should be responsible for airtightness works during my project?

    Obviously every project is unique, and this will depend on whether you are a self-builder, have a builder doing the work for you, or have a Project Manager. However you’re doing it, we would advise that you make someone senior on site (who is going to be around for the whole build) responsible for airtightness. Lots of airtightness jobs need to be done at a specific time, so if someone is responsible for them, this will ensure they don’t get missed. In addition to this, making sure the person responsible is clued up and understands why airtightness is important is key.

  • What if I need help or support with airtightness?

    As a stockist for Pro Clima we can offer support to you to help you select the right product for your project, so please get in touch and we would be happy to help you.

Retrofit West Trusted Professional