Roof questions

[jammyweb]

I have a question about the roof over a pompeii style oven

I have built a dome and intend to build a "house" around it. When I get to the roof, which I intend to tile, should I use felt under the tiles?

I am concerned that even though there will be a lot of vermiculite insulation over the dome, the heat might be too much for the felt.

Any input welcome.

Also see my thread in barter/trade for fire bricks in southern UK.

James

[wlively]

Re: Roof questions

If you are using ceramic blankets and loose vericulite over, then you have nothing to worry about. I have three layers of insulation and a wood roof, no problems.

If you are using vermiculite concrete alone, then it would be a good idea to add another layer, either ceramic blanket of loose fill vermiculite.

[Rastys]

Re: Roof questions

jammyweb
I have put a single layer of superwool blanket over my bricks and then 3" vermiculitr cement over that and topped it off with a 1/2" render finish.
When my oven is cooking at 500˚C, the outside top of the Ponpeii dome is barely warm
You should have no worries at all.
Can you answer me what is the reason that you wish to put felt (and I'm assuming that is similar to carpet underlay felt rather than the quite expensive other dressing, polishing, hard felt) under your roofing tiles?
Are you intending to use terracotta, cement or pressed metal tiles?

Rastys

[dmun]

Re: Roof questions

Building felt, in the US, is the term of art for what we would call tarpaper. Nothing like the wool fabric. It's pretty standard under all types of roofing, and before the new building wraps came in, it was used under siding and cedar shingles as well.

[Rastys]

Re: Roof questions

Thanks Dmun,
we have a similar material that is used as a reflective aluminium foil covered tar paper insulation membrane. I have never heard it called felt before. My home addition has it on the cavity side of the timber veneer walls and under the cement roofing tiles.
It is now coloured light blue to cut down on reflections and blinding the installers and workers in the building trades.

Cheers.

[brickie in oz]

Re: Roof questions

The tar was dropped from the recipe 20 odd years ago.......

[jammyweb]

Re: Roof questions

Thanks for all the replies.

I have a firebrick/storage heater brick dome, which I'm covering with about 6" of loose vermiculite.

I wanted to put the felt/tarpaper under the tiles just to give better weather protection. Partly because I live in the UK - so lots of rain, partly since this will be my first roof tiling of any kind, I'm not too confident. The tiles will be concrete slabs.

Still - how hard can it be - what could possibly go wrong

James

[Rastys]

Re: Roof questions

brickie in oz
My home extensions were completed over 25 years ago, so I guess they had tar in them!