Warm Room Loft and Insulation Moved to Rafters - Is Ventilation Required?

by **Silver_Badger** » Wed Oct 14, 2015 12:13 pm

Hello,

We recently moved into a new house and to get some more storage space I have moved the secondary layer of insulation from over the top of the joists to between the rafters.

I am now concerned that I should have left a gap between the insulation and the felt. Do I need to take it down and redo it?

The house is a 1930s semi. The felt looks to have a transparent plastic backing I assume to prevent water ingress. There are no vents at the top of the roof, but there are a row about 1.5 ft from where the roof meets the joists (eaves?). The insulation is plastic wrapped glass fibre I think. Orange on one side and silver on the other.

Can anyone help? I have seen corrugated "baffles" which can be installed between the roof and the insulation, but these seem to be mostly on American videos and sites so I don't know if they are available. I'll try to add some photos.

Many thanks,

Henry.

by **thedoctor** » Fri Nov 06, 2015 6:51 pm

The insulation is there to stop the heat leaving the house and going into the loft (which should be cool) not to stop heat leaving the loft. Replace the insulation onto the floor and look at our page on Loft flooring https://www.diydoctor.org.uk/projects/bo ... ftzone.htm

by **Silver_Badger** » Sat Nov 07, 2015 8:30 am

Hello,

Thanks for the reply. As I understand it there are two models for insulating the top of the house:

1. Warm loft. This is when you insulate against the roof like they do in loft conversions.

2. Cold loft. This is the more traditional method of insulating above the rafters.

I'd like to achieve the warm loft option if I can. Just not sure about this ventilation issue.

Many thanks.

Henry.