Replacement Flat Roof Requiremnents

[del73]

I am in the process of replacing my flat roof and have had a few quotes all around a similar price. The roof will be a warm roof. The materials I have been quoted for are below.

Quote One.
1. 100mm insulation
Layers
1. SBS torch on venting layer
3. SBS torch on 3.0 premium underlay
4. SBS Techatorch mineral 4.2mm

Quote Two.
1. British Standard 1200 x 600 Eco-Therni, Eco-Torch 120ml insulation boards.
Layers
1. universal 3b glass fibre based felt.
2. 2ml APP polyester torch-on underlay, plain finish APP modified.
3. Andersons high performance Vita polyester cap sheet, finishing with high performance mineral felt flashings and welted edges


Are the materials quoted above the standard industry materials and is either of the above considered a superior product?

For a warm roof is it essential to 'Seal' around the roof joists with insulation to stop air flow?

Are there any other details I should request from the roofer before the works starts?

Thanks Del

 

[ree]

If you post pics of the roof in question it will help with advice.
And if you post prices quoted it will help other DIY'ers with similar difficulties.

 

[del73]

I do not have any photos but it is a felt roof with mineral chippings.

To add a warm deck roof, approximately 80m2 (new boards and insulation), the cost is 7500 + VAT.

 

[noseall]

100mm is not considered enough on its own. 120mm is more like it. As long as they are using rigid foam board insulation i.e. Celotex, Kingspan or equivalent then you will achieve the correct thermal values.

Have you submitted an application to BC?