Truly DIY SIP construction…

[G and J]

1 hour ago, JohnMo said:

Taking a pragmatic look at this. You will have larch everywhere except the end of the building which will be some sort of non combustible so will not look the same as the rest of the building. So instead of doing the same effect with different looks which may look odd. Do the polar opposite, do a finish on ends completely different. 

 

Not saying do this, but as an example, we have a mix of cladding and stone slips. So your end walls are fully compliant you get a different design feature and the different design may actually lead to a thinner wall (maybe).

 

A couple of different images

 

Interesting idea.

 

The non larch bits are either glass or render and I think the render will be ok on the same wall build up as the larch.  (Dangerous thing, assumption!)

 

We put a lot of thought into the look of our new pad and we’d be disappointed if we have to change it, plus, I’ll not be going back to the planners unless I have to.  They’re lovely, helpful peeps but it slows everything down so much!

[joe90]

3 hours ago, G and J said:

I’ll not be going back to the planners unless I have to.  They’re lovely, helpful peeps but it slows everything down so much!

Are you taking the pi@@ ? Never heard that about planners before.

[G and J]

14 minutes ago, joe90 said:

Are you taking the pi@@ ? Never heard that about planners before.

We bought our plot with outline permission in ‘91.  It had gone through and the planners fought us on detailed every step.  Most unpleasant.  We clearly suffered because we tried hard to plan a build that looked dead right for the road/village, meaning we had little to concede to let the planners feel they had won.

 

A few years later we bought some field behind us for extra garden. The planners were just as difficult.

 

A few years after that we decided to extend.  Put in our plans with much gritted teeth and trepidation, despite again working hard to design for looking right and not disadvantaging anyone else.  We were  in for a shock.  
 

The planners were lovely, could not have been more helpful.  They seemed to recognise that we were trying to do the right thing and they responded accordingly.  They even made suggestions that improved our design.

 

A few years after that we had cause to apply in the Lake District for conversion of part of a garden to parking space.  In a conservation area and the National park.  Again they were lovely and helpful.

 

Our experience this year was also good.  In fairness we tried hard to design a house which would look right for the area so maybe many would view our plans as lacking ambition, rather staid perhaps, but the planner put the time into feeding back on our pre app, we followed the suggestions made so I can’t but view their service to us as professional and helpful.

 

 

[Iceverge]

15 hours ago, Gus Potter said:

bit that is hard to do is not actually the cladding spec but how you fire protect the cavity but still allow for ventilation of the cavity

 

I have been wondering about this,

 

Suppose you had a completely non combustible cladding like fiber cement, on fiber cement battens over rockwool. 

Would the cavity be mute then as there's nothing to burn in there?

 

However as there is timber involved, ventilation behind it is vital to ensure it doesn't rot. I gather you protect this from fire by compartmentalizing the sections, normally with fire stops of some kind. However doing this obviously blocks the ventilation too. Unless the natural gaps between the uneven surfaces of the board would provide enough ventilation?

 

What about 20mm over 20mm vertical fire treated cladding screwed onto 20mm horizontal battens at 600cc with solid blocks between inner cladding timbers to ensure no vertical paths Then vertical rockwool filled socks every say 1200mm to compartmentalise any fire to a 1200*600mm square.

 

Then allow the natural small twisting of the cladding to provide a minimal amount of ventilation to each rectangle. Gut feeling says it would work and would also prevent fire from spreading behind the cladding. 

 

@G and J I was just thinking that's how vertical cladding is normally installed. probably an overkill and you could drop back to 1 layer of battens. 

 

 

[ADLIan]

It's all to do with risk. Typical 1 or 2 storey house is not particularly high risk - fire is probably internal and any damage will be limited to the dwelling itself. In high rise, over 11m, this chimney stack effect and risk of fire spread to other properties/flats is just too great. Open state cavity barriers (expensive!) are used in this scenario - an intumescent strip on the front of the cavity barrier expands in the heat to block the ventilation path and stack effect.

[AdTee]

I'm about to stick build our 2 storey wrap-around extension and we're building bang up to the boundary on both sides. We're the end terrace of a small row of victorian cottages, so one side we're around 30cm from a conservatory, and the other side we're around 3m from the flank wall of the next house. We're tight on room, so the wall make-up as per plans (I may change the insulation if I can get better acoustic properties within a similar depth and still meet the required U value) is:

skim
37.5mm insulated pb with taped joints
120mm Kingspan K112 between studs
140x38 studs (can't remember if spec'd as C16 or C24, but will use C24 as that's what my local sawmill carries)
Non-combustible sheathing (just about to start looking into options for this)
Breathable membrane
Cross battened
Standing seam steel

We'll have normal (unprotected, not fire spec) alu non-opening high-level windows on one flank of the ground floor only. There's a max area that you can have for unprotected openings, so I'll put in a fire door to compartmentalise the the ground floor (where new rear kitchen meets new side hallway) as fire resistant windows are sooo much more expensive.