A Timber framed house with external wall insulation

[ProDave]

12 minutes ago, Stones said:

How much wider than the window is the cill?

Plenty. they were in fact to long so the builder shortened them so they are now about 20mm wider at each end than the window.

In my case with the wood fibre cladding, I cut a slot in the cladding at the correct angle and then slotted the wood fibre board panel in, so the end of the windows cill sits in the slot in the wood fibre to support it. I then sealed all around that joint both sides with Stixall, just in case the render doesn't properly seal.

[lakelandfolk]

Re use of wood fibre boards + render Versus cavity block work +render.   I read somewhere that mortgages and insurance are less favourable, and that some providers will not even consider properties that do not have external masonry walls.

Has any one had experience of this?

[ProDave]

Yes, some insurers will class it as a "non standard biuild"  I think the advice on the old place, was go to a broker, and they will find you a policy.

[ProDave]

Just finished the cladding and render of the back of the house.

More on my blog at http://www.willowburn.net look for the entry "and yet more cladding and render"

That's the whole of the house insulated, clad and rendered.

Next is the garage, which has the complication of not having a door and a window yet, something I am trying to source without breaking my tiny budget.

[jack]

Looking good Dave - really clean finish you're achieving!

[gavztheouch]

Hi Dave I like you building method of 8 by 2 studs with external insulation. I am gravitating to that solution as well. The other option being engineered I beams and blown insulation but with less insulation on the outside. 
 

If you had to build the frame again would you still chose the 8x2 method or would you change something. The only downside I can think of is the movement of the 8x2. Does a wider board move as it drys more than say a 6x2 or 4x2.

 

I guess that’s the benefit of engineered timber. I just don’t like relying on glued wood as part of a system that’s hopefully got a life time of 70 years plus.

[ProDave]

I didn't seem to suffer any warping or twisting of the big structural timbers. The frame did sit a while before getting boarded out inside so I guess it had a lot of time to settle. there are no cracks in the plasterboard or plastering or anything at all to suggest structural movement or shrinkage.

 

That is more than I can say for the smaller non structural stuff like 4 by 2's for stud walls that seemed to delight in warping or twisting just to wind me up.

 

The only thing I am not entirely happy with is the thin coat render. I have an ongoing problem with the top layer delaminating in a few places. the investigation and remedial work to correct that is on hold due to the current situation. But even when the defects are reworked, it leaves the feeling of a render system that is not robust and may give further trouble in the future. I long for the dependability and longevity of a cement render but that would have meant blockwork walls which was what I wanted to avoid.

[Jason L]

Hello !   nice looking house and render,  i'm planning on my build having K render on a timber frame, i'm having trouble sorting the telescopic vents out with which is effectively a single skin of blockwork below the dcp.     How have you done it so that the air bricks are flush with the face of the blockwork ?  J

[ProDave]

I have not rendered the blockwork below DPC, i chose just to paint it with grey masonry paint.  That part is below the joists and not covered by the EWI so the air bricks just go straight through to ventilate under the joists.

[Jason L]

1 hour ago, ProDave said:

I have not rendered the blockwork below DPC, i chose just to paint it with grey masonry paint.  That part is below the joists and not covered by the EWI so the air bricks just go straight through to ventilate under the joists.

Ahh it maybe what I just thought off.  I just looked again  It looks like they are well below the FFL  so they are not telescopic z vents ? 

[RDodds89]

Hi, dragging up an old post here.  But instead of rendering onto the insulation boards, could you baton and then clad with UPVC/cement boards?   At the beginning of doing a DIY extension, at the moment with the idea of a warm flat roof, so the idea of external insulation on the walls is tempting too.  Thanks 

[ShepardsHut]

On 26/06/2016 at 12:03, lakelandfolk said:

Re use of wood fibre boards + render Versus cavity block work +render.   I read somewhere that mortgages and insurance are less favourable, and that some providers will not even consider properties that do not have external masonry walls.

Has any one had experience of this?

Hi,

Yes tried to get a green mortgage on my wooden house and non of the big players are interested and then the ones that are charge double the interest.

[Big Jimbo]

10 minutes ago, ShepardsHut said:

Hi,

Yes tried to get a green mortgage on my wooden house and non of the big players are interested and then the ones that are charge double the interest.

Yes , i have been told that many, many times. It's about time the mortgage companies woke up to the new construction methods that are now in use. Buy a 130 year old damp, drafty, e, energy rated, old brick property....mortgage no problem. Modern A rated timber house....Sorry sir.... It's a joke ....

[SimonD]

On 08/06/2021 at 13:22, RDodds89 said:

Hi, dragging up an old post here.  But instead of rendering onto the insulation boards, could you baton and then clad with UPVC/cement boards?   At the beginning of doing a DIY extension, at the moment with the idea of a warm flat roof, so the idea of external insulation on the walls is tempting too.  Thanks 

 

Yes you can. The detailing obviously needs to change somewhat as you need to fix the battens through the wood fibre into the timber frame/masonry wall. Having a rainscreen outside the wood fibre insulation is recommended now in several parts of Europe to protect against wind-driven rain. I have to say, next time I use wood fibre I would swap out the direct thin coat render for a rain screen. Much better insurance long term, I believe.

 

HTH.

[JamesP]

On 08/06/2021 at 13:22, RDodds89 said:

Hi, dragging up an old post here.  But instead of rendering onto the insulation boards, could you baton and then clad with UPVC/cement boards?   At the beginning of doing a DIY extension, at the moment with the idea of a warm flat roof, so the idea of external insulation on the walls is tempting too.  Thanks 

I have 40mm Pavatherm fixed to timber frame, then membrane, batten, counter batten, Cedar cladding.

Put some stainless steel rodent mesh top and bottom behind the cladding.