Kan man forsegle et eternittag?

Can you seal an eternit roof?

Eternit is found on many Danish garages, carports, outbuildings and older houses, and at some point the sheets start to look tired. Then the question arises: should the roof be torn down and replaced, or can it be saved? On most Eternit roofs, it can be saved, but there is one thing you need to clarify first.

How to wear down an eternit roof

Eternit is fiber cement, and the surface becomes porous over the years. This happens slowly and for several reasons at once:

  • UV breaks down the surface, causing the sheets to become rough and absorb water instead of wicking it away.
  • Moss and algae settle on the rough surface and retain moisture throughout the winter.
  • Frost expands the water that has penetrated, and hairline cracks become real cracks.
  • Joints, overlays and penetrations are where the leak starts, not in the middle of the slab.

An eternit roof rarely breaks with a bang. It just gradually becomes more leaky until there is water in a place you can't see.

Tagmembran påføres med rulle i ét lag

Asbestos must be cleared up before anything else

Older eternit sheets may contain asbestos, and this changes the entire procedure. If you are in doubt about your roof, get it clarified before you touch it.

  • The roof must be stable, clean and dry before application.
  • If the roof contains asbestos, cleaning and preparation may only be carried out in accordance with applicable regulations.
  • If in doubt, contact an authorized asbestos removal company.

It is worth noting that a membrane works with and not against the problem here. It is laid on top of and encapsulates the surface after proper preparation, rather than the panels having to be broken up and hauled away.

When the roof is ready

The work itself is the same as on roofing felt. The membrane is pre-mixed, applied with a roller or brush in one layer, and no gas torch, welding or multi-stage primer is required.

  • Clean the roof thoroughly and let it dry completely, not just on the surface.
  • Check the overlaps, edges and penetrations first. This is where the roof will leak.
  • Roll the surface in one layer. Consumption is approximately 1.5 kg per m².
  • The temperature must be above 5 degrees, and the weather must be dry throughout the drying period.
Tag forseglet med Luna Roof tagmembran

What you are left with

A seamless surface without joints, and that's the whole point of a roof where the problems were precisely in the overlays. The membrane is 100% waterproof, resistant from minus 40 to plus 90 degrees and has reinforced UV protection, so it won't become brittle again from the sun that wore down the old roof.

There is a 25-year product warranty, and with correct application up to 40 years of service life. The membrane is fire classified Broof (t2) according to EN 13501-5 and CE marked according to EN 1504-2, which is stated on the data sheet together with ETAG 005.

How much do you need?

A 20 kg bucket covers up to 13.3 m² in one layer. A garage roof of 40 m² corresponds to 3 buckets. The membrane can be laid on eternit, roofing felt, concrete, slate, zinc, roofing foil, metal and wood, so the substrate is rarely the problem.

See roof membrane for eternit roofs and calculate your consumption

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