replace existing cold flat roof on extension

[novicetodiy]

Hello

Our existing flat roof is leaking, and looking to replace with warm installation.

the area to cover is 19m2.

I thinking of using Celotex TD4126 flat roof insulation deck , with consists of 5.5mm WBP ply deck, vapour control layer and 120mm insultation.

Trying to put a shopping list together for this project - My questions are;

1. in between the roofing joists and the celotex insulating deck, the document says to run a " bed onto twin beads of vapour sealant wide enough to accommodate this . Also apply this Where boards butt together."

What type of sealant are they refering to, is it some type of mastic?

2. after we lay this insulating desk on top of joists , what additional layers are required?

e.g. underlay and traditional roofing minerial. The technical document refers to

Document refers to "Always use a Type 3G felt to BS 747 as a vapour
diffusion first layer when using BUR weathering systems. When using a single-ply membrane,additional 12mm plywood has to be applied on
top of the Celotex TD4000."

Can you recommend any specific products?

3. The document also refers to specific fixings; with corrosion proof suretwist composite panel helical fasteners.

What are these?

thanks

 

[htgeng]

What document are you referring to? A quotation?

 

[novicetodiy]

Hello.
Sorry forgot to post the PDF document. This is the celotex handy guide from the website. Please refer to pages 34-35.
Thanks

https://docs.google.com/viewer?a=v&...YjUzOC00YjY2LWJkZTItYzI5OTk0N2I5NWYz&hl=en_US