Airtightness in an insulation layer

What an air leak actually costs

Insulation with a draught passing through it loses much of its effect, whatever its thickness. Warm air goes out, cold air comes in, and the insulating material is merely a spectator. That is why careful work on airtightness often recovers more than an extra centimetre of insulation.

The comparison that makes it obvious

The human body is the best example. We breathe through the nose, at one controlled place, not through the skin. A house works the same way: it has to be airtight everywhere and ventilated at a chosen point. A house that breathes through its defects is a house that wastes.

How airtightness is obtained here

R'BULL Pro 13 is airtight by construction, through the sealed air bubbles and the two aluminium faces. The product itself lets no air through. Everything therefore depends on the junctions: overlaps, edges, and the points where conduits and light fittings pass through.

What is left to do on site

Overlap the lengths, run a continuous aluminium tape, and treat every penetration rather than leaving it open. That part cannot be improvised and is the real work of fitting: unrolling the roll itself is quick.

The full method is shown on the page about fitting airtight insulation, and the product on the R'BULL Pro airtight page.

The test that settles the argument

A blower door test puts the home under negative pressure and measures the leakage rate. It is inexpensive next to the cost of the works and it points to the defects one by one, instead of leaving everyone to guess where the draught comes from. It is the only way to know whether the airtightness work was done or merely invoiced.