Warm flat roof dilemma

[Rustytabitha]

Hello I am endeavouring to future proof my home due to disability (MS) by making improvements like warm roofs bathroom and kitchen upgrades. Having had a couple of  bad experiences with trades I am keen to get things right first time. 
my current dilemma is which roofer to use for a large flat roof project. One plans to replace everything make it warm and make a larger roof light etc and he uses fleece backed EPDM and an alutrixx vcr. The other wants to use existing felt as a vcl and put single ply pvc  sika sarnafil or IKO Armourplan on top. Which should I choose and why? I haven’t got a quote for GRP. 
size of garage carport plus smaller roof. What do you think fair cost might be? Thank you. 

[JohnMo]

Not really clear what you are doing to the roof.

 

A warm roof typically is externally insulated.  The fleece backing will add little or no additional insulation value.

 

If your roof covering is sound, you could insulate and then add the new covering. To give a warm roof.  Typically you should be looking to add 150 to 200mm of insulation.

 

What roof buildup is each installer offering, have you asked for a specific buildup?  Or just leaving it up to them to offer what they think you want?

[Rustytabitha]

No fleece backed refers to the type of rubber roofing material. The fleece is for cushioning/reinforcement of the material not as an insulation. There is a decking out on the roof then VCL then insulation material then either another deck then roofing material or if it is roofing insulation you can walk on straight on top. I was asking which was preferable fleece backed EPDM or PVC. Thank you for your reply. 

[JohnMo]

We have Silks Sarnafil on our roof.

 

Reasons, only supposed to be installed by correctly trained fitters.  Fully welded install so less chance of leaks.

 

Our Sarnafil has a loose fit fleece between it the plywood deck.

[Thorfun]

our roofer used Alwitra VSK single-ply. I was told by two different roofers that for our timber frame and due to the potential movement of it GRP was not a good solution.