Green Building Forum - How Big A Gap Behind the Cladding?

How Big A Gap Behind the Cladding?

Triassic — Tue, 01 Jul 2014 09:49:05 +0100

I'm wondering how big a gap to leave behind the cladding, looking on-line suggestions range from 10mm to 50mm and sometimes even bigger (Archmoco wins the prize for the biggest - wow 300mm).

The building is timber frame and I'd like to keep the cladding battens as thin as possible to maximise internal space. Any suggestion as to absolute minimum?

How Big A Gap Behind the Cladding?

owlman — Tue, 01 Jul 2014 10:30:35 +0100

Treated 25mm tile battens?

How Big A Gap Behind the Cladding?

Cerisy — Tue, 01 Jul 2014 10:43:46 +0100

Agreed owl man - treated 25 x 50 battens. Used loads of them behind our cladding and will use even more to create our services space behind the plasterboard. Just have to be selective with the really bent ones!!

Make sure you close off at the bottom of the battens with insect mesh.

How Big A Gap Behind the Cladding?

Paul in Montreal — Tue, 01 Jul 2014 11:51:32 +0100

Over here the standard is to used 1x3s - not necessary to use treated wood as it's a vertical drainage plane ( you nail the battens in vertically, not horizontally). These gets nailed on top of the tyvec and the cladding is nailed to these battens. Google "pressurized rainscreen construction" and you'll find all the details. 1x2s are too narrow to be a good target for nailing the cladding to.

Paul in Montreal.

How Big A Gap Behind the Cladding?

owlman — Tue, 01 Jul 2014 12:37:56 +0100

Agreed Paul, no need to use treated, but treated tile battens are so universally available and hence cheap, if you start asking for untreated or simple sawn timbers of an equivalent size you may end up paying more. It may not be worth the effort.

How Big A Gap Behind the Cladding?

Paul in Montreal — Tue, 01 Jul 2014 12:50:56 +0100

I still think 1x3s (or even 1x4 around windows) are better than 1x2s as they're less prone to split if you don't get the nails for the cladding dead-centre. The battens should always be arranged such that no water can accumulate on them too (even if using treated).

Paul in Montreal.

How Big A Gap Behind the Cladding?

Cerisy — Tue, 01 Jul 2014 13:19:16 +0100

i had no problem nailing to my 1 x 2's Paul - with the nail gun of course!! You can see the battens as you go up. Yes, it's a ventilated vertical space, but it will be at the same humidity as the air and that can allow fungus to develop. I would agree with Owlman and do the belt and braces treatment. I did add extra battens around the window / door reveals, where the porch will be fixed over the back door, where the sat dish is going to be fixed, etc. Fortunately I have photographs records of them all!!

Jonathan

How Big A Gap Behind the Cladding?

CWatters — Tue, 01 Jul 2014 19:21:08 +0100

Nailing to 2" battens is ok. Have a think how you plan to support/seal the butt joints in long runs. I fixed two short lengths of batten either side of the join. You want them far enough from the join that the cladding won't split. Then I fixed a strip of membrane so that any water going through the join would be directed to the outside and onto the cladding strip below. Excess membrane was trimmed off after the cladding was fixed.

How Big A Gap Behind the Cladding?

nikhoward — Wed, 02 Jul 2014 03:42:39 +0100

Posted By: owlmanTreated 25mm tile battens?

That's what we used

How Big A Gap Behind the Cladding?

Archmoco — Sun, 13 Jul 2014 16:39:43 +0100

Posted By: TriassicI'm wondering how big a gap to leave behind the cladding, looking on-line suggestions range from 10mm to 50mm and sometimes even bigger (Archmoco wins the prize for the biggest - wow 300mm).

The building is timber frame and I'd like to keep the cladding battens as thin as possible to maximise internal space. Any suggestion as to absolute minimum?

My gap was calculated to be deep enough to hide the slight roof over hang, gutters and vertical studs to support timber cladding.

If you are timber cladding onto blockwork then batten size will depend if you cladding is horizontal or vertical and spaces between battens, you want to ventilate top and bottom, so strictly speaking for vertical cladding you will need to counter batten, to ensure clear air path.

With my fibre cement I just used horizontal treated 44x44mm, although I did pack the space between with PIR insulation, but then the corrugated profile give a minimum void of 22mm

Regards Archmoco

How Big A Gap Behind the Cladding?

djh — Sun, 13 Jul 2014 21:04:53 +0100

1mm?

http://www.nbec.net/documents/REQUIREDDRAINAGEGAPSIZEFOREFFECTIVEDRAINAGEBEHINDVARIOUSCLADDINGS-JOHNSTRAUBE.pdf

Whatever size you choose, detailing at corners etc is important. Straube et al have various documents about it but I don't remember exactly which ones.

How Big A Gap Behind the Cladding?

Triassic — Wed, 06 Aug 2014 10:58:11 +0100

Came across this document, which some of you may find helpful. It suggests a minimum of 19mm gap behind timber cladding. http://www.scotland.gov.uk/Publications/2002/03/15098/8744