Okay with foam plastic under exterior roof? Insurance company/fire risk

[Johan1983]

I have a question regarding insulation. Can you use foam plastic under the outer roof without insurance companies, etc., getting irritated?

I have seen that it can become a fire risk if, for example, you have it on the facade.

 

[Johan1983]

The headline was a bit wrong

 

[Marlen Eskilsson]

Fixed!

 

[Peter2400]

Fixed!

What have you fixed?
The title is still about spotlights and the post about insulation.

 

[justusandersson]

Cellplast should preferably be placed behind a fire-resistant material such as concrete or plaster. It is also not suitable for installation between studs.

 

[Johan1983]

Polystyrene should preferably be placed behind a fire-resistant material like concrete or plaster. It's also not suitable for mounting between studs.

Ok, no polystyrene in the ceiling then. Neither outer ceiling nor inner ceiling.

 

[KnockOnWood]

I have 100 mm of foam plastic on top of the roof's raw cladding.
Above the foam plastic are battens, support battens, and concrete tiles.
The house was built in 2010.

I see no problem with this, and evidently neither have the quality managers, inspectors, or insurance companies had any objections.

 

[justusandersson]

I have 100 mm foam plastic on top of the outer roof's raw wood.
Above the foam plastic, battens, counter battens, and concrete tiles.

This should be OK according to BBR when it comes to a small house that has at least 8 meters distance to others. However, one should be aware of the risk of fire spread if there is a fire nearby. Personally, I wouldn't choose that solution, even though it's a great idea to have an external insulation layer.

 

[Fotografen]

For me, it's simple, cellular plastic has far too poor fire properties to exist in, on, or above my house. Possibly in the foundation, under the concrete slab.

 

[bossespecial]

Cellplast is like gasoline in solid form, not great to have in a house....

 

[Finndjävel]

If you have a wooden house, I find it a bit strange to fixate on the fire properties of foam plastic. A wooden house will probably burn down with or without foam plastic if it catches fire.

 

[justusandersson]

There I disagree. There is a big difference in the amount of toxic and highly flammable fire gases that foam plastic emits compared to wood. If you have seen the incredible devastation that a fire in foam plastic can lead to, you would preferably want to avoid such an event.

 

[KnockOnWood]

Then it is probably worse with all the foam plastic, foam rubber, and whatever it is called that we have in our furniture and mattresses indoors. It's probably mostly that which kills us in a fire, due to the toxic gases released.

 

[Finndjävel]

Toxic, absolutely, but a wooden house that catches fire becomes fully engulfed in 5-10 minutes, so you're unlikely to save such a structure even if it doesn't contain any cellplast.

 

[bossespecial]

Wood absolutely burns. However, wood does not have the same explosive fire development. If a welding spark lands on a wooden facade, it will basically leave a small charred mark, while foam plastic would ignite the entire facade within seconds.