Yes. Enjoy, and if you can resist the temptation (or pressure from 3rd parties) to hide the frame behind brickwork, all the better. May be one or 2 stipulations re flammable material and distance from boundaries.

Send some pics when it's done.

Nick

Try this for one option:

http://www.natural-building.co.uk/pavatex_timber_frame_wall_systems.htm

Thanks guys,will take a gander.

Yeah Tony,realise now i don't need a cavity after doing a bit more reading up.I know all about planning and building regs,having worked as a joiner builder for over 30 yrs.I have been involved in loads of different builds over the years but they have all been traditional brick block construction.I am geting more interested in sustainable building and i think future clients will be so i thought what better way to start to learn new techniques than building something at home.

Will probably be rendering as the rest of the house has been rendered at some point and like the look of the pavatex system posted above.

Thanks woodbutcher! It's a quick way of building, but produces a well insukated space with breathable walls.

The living space breaths via controlled ventilation. The walls breath outwards, we wouldn't want to lock in moisture would we?

richy -- so a vapour barrier then?


woody -- with different forms of construction joined into one house there will be differences in thermal performance and thermal movements -- the worst cases which will be rare hopefully will be condensation and mould problems due to unfortunate cold spots which would be nightmarish if below the surface.

Tanks for that Tony,more room for thought.

Cheers For that Doc.Mine will be rendered.Can you point me to anywhere i can get some info on the method you used?

A warm roof is a timber construction and has no cavity so why should a wall need one?

Dormer walls have no cavity either and they are often timber framed.

Not at all convinced about the necessity of a cavity -- who is saying this?

Posted By: TimberA cavity IS required with a timber construction.

Anytime you use timber frame, it MUST be provided with a drained and ventilated cavity.

Are you just talking about the air gap and drainage plane behind the rain screen - to deal with any small leaks and condensation?

You may not need an extra blockwork leaf on the outside to aply the render to, you can use a lightweight render system supported by the timber frame, but you will require a cavity.

Assuming you apply render at all, of course.

....Edit - that pavatex and diffutherm products are not really suitable for use with timber frame. NHBC have recently updated their timber frame section of thier technical requirements, and now clearly state that they do not accept these sorts of systems, unless they are appropriately 3rd party certified. These products do not have any third party certification and so can't be used. Just to warn anyone out there looking at them, you may come unstuck with warrenty providers or building control.

So why are NBT selling Pavatherm, etc, knowing it's for use on timber frame houses?

Timber, Why can't you use PUR insulation in timber frame? What's the difference between say infilling between rafters/studs in an existing house and new timber frame buildings. Both celotex and kingspan have BBA certification for existing applications don't they? I would have thought they also have them for timber frame as any risk of interstitial condensation is arguably less of a risk in a correctly detailed new build. Don't they have such certification?

Ed: "Are you just talking about the air gap and drainage plane behind the rain screen - to deal with any small leaks and condensation?"

Timber: "Yes thats correct."

Fine, but that's sufficiently different from what people think of as a "cavity" that it would have probably been worth making it clear.

Timber: "Well the OP stated that they were going to apply a render finish to their TF extension"

Ok, sorry, missed that.

Ed: "So why are NBT selling Pavatherm, etc, knowing it's for use on timber frame houses? "

Timber: "Why indeed!?"

Sorry, I helped out a couple of weeks ago putting Pavatherm on friend's oak frame self-build reasonably-large extension. Everybody involved, the BCO, NBT (the MD of which is a school friend of my friend), the oak frame suppliers, etc, are all quite happy with the design.

Roof inside to out is exposed oak rafters, plasterboard, 2 x 80 mm layers of Pavatherm, Isolaire, counter-battens, battens, reclaimed tiles with some hemp in the eaves. (Pause in the build at the counter-battens stage for now.) Walls will be plasterboard on battens, OSB, hemp (can't remember the thickness), PavathermPlus, battens, larch (I think he's decided on) cladding.

What do you think is the problem with this?

Timber, I have searched th BBA website and you are correct about the TF specification. I am surprised at this as Kingspan carry BBA certification for between and above rater applications.[both cold and warm roofs] See http://www.bbacerts.co.uk/certs/31/3126i3_web.pdf

I fail to see the technical difference between roofs and walls as either can utilise the same design if necesary. I wonder why PUR cannot be used in timber frame walls. Can anyone explain this mystery

Can I ask which software you are using for your condensation risk analysis? From what you say, a typical roof build up would fail as well.

Ta, downloading it now. I usually use Tas so will be good to compare results