DIY Doctor

Main navigation

Size of Air Gap on Pitched Roof for Single Storey Extension

Postby lesrico » Thu Dec 14, 2017 10:23 pm

I’m building a single-storey, pitched roof extension which includes a vaulted ceiling (9” deep trusses).

Building inspector said I can put 8” thick mineral wool roll between the rafters on the sloping part of the vaulted ceiling, leaving a 1” gap for air flow between the top of the insulation and the tiles. I presume that this air gap will allow air flow from soffits upwards to the ridge, preventing condensation build up.

However, my builder has expressed concern, stating this is a mistake as 1” is insufficient airflow. He has suggested that I do away with the mineral wool roll and buy Kingspan boards (at 4 times the cost!!).

I just wondered if anyone out there can offer any advice?

Thanks in advance.

Rank: Labourer
Progress to next rank:
Posts: 1
Joined: Thu Dec 14, 2017 9:43 pm

Postby michaelscad » Tue Dec 19, 2017 3:42 pm

50mm minimum ar gap between insul. and tiles
Rank: Tradesman
Progress to next rank:
Posts: 49
Joined: Sun Sep 17, 2017 12:58 pm

Display posts from previous
Sort by
Order by

  • DIY How to Project Guides
  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!

  • Related Topics