Proctor Promotes Good Practice: Installing membranes for long-term performance

A vapour control or airtightness layer only provides its declared performance for as long as the membrane remains intact and undamaged.

It’s a noted problem on construction sites of all types and sizes that contractors often end up working in a very siloed way. The membrane installation is completed, often to a high standard, only for an element of it to be undone by follow-on trades.

Any disruption to the original work then tends to go unrectified – and the building goes on to suffer the consequences of the modifications that have been made.

The importance of membranes is not always well understood. They play a vital function in building physics but, because they are hidden components masked by the final finish, they can end up being neglected.

The projects we see deliver construction quality most successfully are those that promote a good dialogue between different contractors. When everybody is on the same page and recognises the importance of membranes to building performance, they can carry out their work accordingly.

On one project that used our Wraptite® system, the installed membrane was treated poorly during the construction programme, to the extent of it even being damaged in places. It seemed as though the membrane was viewed as temporary protection rather than a crucial component of the facade build-up, and resulted in unnecessary remedial work.

Understanding the importance of membranes is more than just appreciating their contribution to a building’s physics. It’s also recognising how they interact with other components around them, not least the substrate to which they are attached.

A lot of high-rise projects we supply membrane products to feature concrete frames. Preparation of concrete substrates is an excellent example of what we’re talking about, and vital to successful membrane attachment. Key steps include ensuring the substrate is smooth, and free of laitance and dust must be brushed off the concrete.

When we speak to contractors and installers about different membrane solutions, some will say that they don’t need to change their approach. Airtightness is an excellent example, with people satisfied that their methods can help to achieve a performance of, say, 7 m³/m²/hr.

Are their methods good enough to contribute to better rates of airtightness, though? Can they help to deliver 5, 3 or even 1 m³/m²/hr on a project?

With tighter building regulations and increased adoption of the Passivhaus standard, better airtightness is essentially now standard across the built environment. Installation needs to be aligned with that expectation to avoid locking in performance gaps for the life of the building – and even risking regulatory non-compliance.

Arguably, the most successful membrane installations are those where the installing contractor considers the whole life of the building, rather than seeing only to the end of the construction phase.

Along with the good dialogue we discussed earlier, true value is delivered when membrane specification and installation considers the end user. What maintenance work will the building require in future? How will typical maintenance impact on what is being installed now, in the construction phase?

It is this kind of holistic thinking that has driven the wider adoption of external airtightness membranes like Wraptite. Moving the building’s airtightness line externally significantly reduces the number of penetrations through it, compared to only an internal membrane that is relied upon to provide both airtightness and vapour control.

Many membrane installers who have seen internal air and vapour control membranes damaged by follow-on trades have switched to Wraptite. The change has paid dividends in terms of delivering high levels of airtightness more reliably, all backed by comprehensive product support, technical expertise, and on-site toolbox talks.

Find out more at https://proctorgroup.com/all-products