Dorma Cladding

21 Jul 2007
Reaction score
United Kingdom
Hi all,

We are looking to change the cladding on the dorma part of the house. Its currently some form of T&G wood which has seen better days.

The plan was to have the wood removed, insulation boards installed, waterproof membrane then PVC (White) cladding installed over the top.

We have had 3 quotes, and they are vary.

1) £1100. Remove wood, install insulation and then make some form of frame?, then install cladding.

2) £500. Remove wood, install 25mm solid board insulation, install waterproof membrane, install PVC cladding (using correct start, stop and corner pieces).

3) £1500. Remove wood, install insulation, install 18mm Marine Ply, install waterproof membrane, install cladding. The Marine Ply will strengthen the dorma...

We think that No 2 is the best quote, as currently there is no Marine Ply on the dorma. Its been standing for 30+ years and its still good. Its just a bit chilly in there, and the best way to update the insulation is from the outside..


Edited... now with Picture..

Sponsored Links
PVC, and nasty.....

Anyway, is the wood actually rotten, otherwise just sand and re-paint.

Other points...

Waterproof membrane should be a breather membrane.

There should be a small cavity behind the cladding and between the membrane, or boards that allow for drainage (always assume water does get into the cavity).

You don't need a board layer, but if you do it is not a boat, you don't need marine plywood. OSB3 or European spruce plywood will do (not cheap chinese plywood).

If you install rigid foil faced insulation onto timber studding, it may need to be about 50mm+ to avoid possible condensation.
Marley Weatherboard is a manmade board, it is textured and looks like wood, is cheaper than pvc, comes in a good choice of colours and is maintainence free.

But I bet he still goes with white pvc.
Sponsored Links
Hi all,

Maybe the Marley is something to look forward too in the future. Priority 1 is to get some insulation into the Dorma walls, as the rear bedroom temperature drops over night more than those in the front. PVC can be fitted next week, and we already have a quote.

One bedroom was built in 2006 as a part of an extension, this room is toasty no matter what time of day it is, the other front is not so bad, however both rears are very poor. Windows have been checked, and they appear to be good in condition, and seals.

Also there is a lack in the insulation in the flat roof, so the plan is to have the walls done with the change of the cladding (as the rear cladding is falling away)..then insulate the loft by sliding boards into the flat roof space from the attic.

Of course, if we wanted to "remove the flat roof, install insulation and fit a new roof, that's £2k per side..."
Does it not strike you as odd that its so much cheaper then the other too?

I would be absolutely sure you know exactly what your getting as it doesn't seem the quotes are like for like so how can you compare them accurately?

At a guess, quote number 2 will end up being similar to number 1 after they take the cladding off and say. ''oh it needs counter-battening, we didn't quote for that...''

'The frame' in quote number one sounds like counter battening but who knows? ask for clarification?

There are so many posts on here from people who take the lovely much cheaper quote and then come on posting ''Is this right? Its leaking? should this be finished better?'' ''they added on this extra...''etc etc
Also in my opinion the marley is much better looking than pvc.

Also its called a dormer rather than dorma, i'm not trying to be smart I only mentioned it because it may help using the right terminology when talking to cladding suppliers etc

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local