Timber frame footings.

[Screech20]

So here's my latest.

Note there will be insulation between the studs. Not sure if it needs to be full filled or if it will cause problems if not.

Have used 140mm blocks to spread the thickness of the wall over.

I contemplated insulated plasterboard as well but not sure if it would be overkill.

Thanks!

 

[tomfe]

Might be cheaper doing 150 or 200mm studword then blown insulation. Or a Larsen truss if you get 3x2 for free.

 

[Screech20]

Thanks for the suggestions.

Am quite happy using the studwork method that I already know. Just need to get these details nailed.

Thanks

 

[Footsoldier888]

Nailed Lol .

I have a TRADA paperback book which has all these details illustrated in great detail but unfortunately I can't get it right now. Got it pretty cheap off Amazon, it will really help you if you are building panels yourself.

I think everyone pretty well builds in 140 studs off a 300 trenchblock type foundation so as to meet the building regs.

I also think if you having a rendered finish direct to the panel you might have to use bigger battens or cross battens. I think it is to do with the weight and needing distance and airflow behind the cement board in order to stop the battens rotting. However this could be wrong.

All I know is very generally it always works out to 300 be it bricks, block and render, or insulation, battens and render on the outer skin.

 

[pilsbury]

As I’m not familiar with timber construction I can’t comment much except it looks fairly sensible.

One thing to add though is the 150mm mot and sand blinding below your DPM and minimum 120mm concrete slab. Depending on if you want to save money I believe 120mm of jablite EPS insulation also meets minimum u values for the floor. Not as good as PIR but still meets building regs at 1/4 the cost. I bet 120mm PIR is £60/sheet vs EPS at £15

 

[Screech20]

Nailed Lol .

Is this sarcasm or am I actually getting somewhere? Lol!

What would be achieved with the 140mm studs? From what I have researched, I can achieve the u value with the 89mm even without the 50mm on the outside.

I’ll look into the render query. I was thinking of one of these thin coat, flexible systems, so think they’re quite light.

One thing I was wondering, with the 50mm over the studs and sheathing, how does the framework ‘breath’?

Thanks.

 

[Screech20]

As I’m not familiar with timber construction I can’t comment much except it looks fairly sensible.

One thing to add though is the 150mm mot and sand blinding below your DPM and minimum 120mm concrete slab. Depending on if you want to save money I believe 120mm of jablite EPS insulation also meets minimum u values for the floor. Not as good as PIR but still meets building regs at 1/4 the cost. I bet 120mm PIR is £60/sheet vs EPS at £15

Thanks mate, I will be looking into this at some point too

 

[Footsoldier888]

Is this sarcasm or am I actually getting somewhere? Lol!

What would be achieved with the 140mm studs? From what I have researched, I can achieve the u value with the 89mm even without the 50mm on the outside.

I’ll look into the render query. I was thinking of one of these thin coat, flexible systems, so think they’re quite light.

One thing I was wondering, with the 50mm over the studs and sheathing, how does the framework ‘breath’?

Thanks.

I think people use 140 studs so all the insulation can go between the studs and for cable access. But if you have a supply of 90mm and can meet regs all well and good I guess.

OK the frame breathes because there is a vent at the bottom above the brickwork:

http://creditohipotecario.info/render-on-timber-frame

I don't know what the foundation width is you need but the sole plate has to be anchored to the ground not the wall, so maybe some space is needed for angled straps bolted into your foundation block.

 

[Screech20]

Thanks for your help.

With regards to the frame breathing, the vent would be between the cement board and the insulation, not the framework?

I may be completely wrong, so would appreciate correction if this is the case, but using an online u value calculator...

89mm studs, insulated inbeween studs and insulated plasterboard with a rendered board requires 50mm of PIR insulation to get a u value of 0.25 (0.28 min requirement)..? (Also leaving me with a service void)

So I don’t actually need the 50mm on the outside as well as inveween the studs?

 

[Screech20]

View attachment 147297

I don’t suppose you’ve got the whole drawing with what the pointers are explaining?

 

[freddiemercurystwin]

It was actually a stone cladding a bit like thick tiles bonded to cement board but it would be the same principle for render.

So for you it would be:

18mm render applied to 12mm cement board mechanically fixed to 38x50 treated softwood vertical battens to create ventilated space on Tyvek Housewrap breathable membrane on 12mm WBP plywood sheathing board (externally) on 125x50 C16 studs at 400 cts with 100mm Kingspan insulation between studs or similar with 1 layer 12.5mm foil backed plasterboard and skim coat internally. Overall construction to achieve U Value of 0.26w/m²k.

 

[AR754]

How did you get on with this? Looking at a similar extension but didn't know where to start. Did planning state anything about fire proofing etc?

 

[Notch7]

How did you get on with this? Looking at a similar extension but didn't know where to start. Did planning state anything about fire proofing etc?

Fire proofing is buildings regs. Is your proposed extension less than 1 metre from the boundary.

 

[AR754]

Fire proofing is buildings regs. Is your proposed extension less than 1 metre from the boundary.

No it’s in the centre of the rear of the property.