Ready to hire?

Post your job in minutes, browse real reviews and choose who to speak to.Post a job

Need some tips or advice?

Insulation

Insulating a flat zinc roof

Anonymous user 23/02/2024 - 2.59 PM

Hey all, I have a old cottage (1860) which has had a flat roof extension added to the rear around 60 years ago. The bedroom under the flat roof is freezing at the best of times so I would like to insulate this but I'm a little unsure of my options. The zinc is in fairly good condition, no leaks and I've been up and seen there has been no patching at all. On one corner its slightly rippled but the water still runs off. Underneath the zinc I have a 160mm joist and then the lath and plaster. The roof doesn't appear to have any vents...? So would I need to insulate from above or could I totally fill the cavity with insulation, use a Vapor Barrier and then plasterboard? Or would I need to leave a ventilation gap as there currently appears to be no vents? Hope all that makes sense.

Are you a tradesperson and able to answer this question?

1 Answer

A&J Surveyors Ltd

Rating: 5 out of 5

Newent

If you remove the ceiling you could insert solid insulation to a depth of 110mm then use a foil backed plasterboard as your vapour barrier. solid insulation will give you better U Values over quilt insulation. Ideally you need to leave an air gap.. Since your zinc is circa 60 years you may wish to consider how long it really does have left. Refurbishing inside then getting a leak would be bad news. The best option is a warm roof with the solid insulation outside and quilt in between the joists. Regards Drew @ Fibertechs - Gloucestershire

Answered23 October 2015