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Timber frame, CPS or SIP


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Hi, looking for some advice on the pros and cons of going with timber frame, CPS or SIP construction for a 1.5 storey rural self-build. Specifically wondering how the various type build affect the future value of the house, and how the speed of construction affects the overall costs (ie if SIP goes up quicker than CPS, does this counter the extra cost of a SIP kit as you’re saving on days of labour?). Any advice welcome! 

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9 minutes ago, AnnaKH said:

Closed Panel System  - so panels are manufactured with insulation in place 

Im thinking Kit House, pre-finished wall panels with outer skin, timber frame, insulation and maybe even inner skin factory installed

Edited by markc
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Is this a property for yourself? How high on your priorities is low heat loss and comfort?

I wouldn't personally use SIP without a masonry outer skin. While U vales on PU filled SIPs can be reasonable, the short decrement delay of PU insulation, without a masonry outer skin won't perform as well as say a cellulose fibre insulation.

 

CPS could mean twin stud panels pre-filled with cellulose fibre. Out of the two options you have mentioned that would be my preferred option, but you could also consider an I Joist, stick built structure with cellulose fibre.

Speed is similar, just the time for the CPS and SIPs is in a factory and not on site.

CPS (as I understand what you mean by it) and I Joist are pretty similar in costs, performance and time, but for me I Joist just edges it (but I'm biased).

 

Edited to add:
I can't see any have a differing effect on value, all things being equal. Without a masonry skin each will have less lenders willing to lend against it, and less insurers willing to insure it, but that doesn't mean that lending or insurance will cost any more.

Edited by IanR
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7 minutes ago, IanR said:

Is this a property for yourself? How high on your priorities is low heat loss and comfort?

I wouldn't personally use SIP without a masonry outer skin. While U vales on PU filled SIPs can be reasonable, the short decrement delay of PU insulation, without a masonry outer skin won't perform as well as say a cellulose fibre insulation.

 

CPS could mean twin stud panels pre-filled with cellulose fibre. Out of the two options you have mentioned that would be my preferred option, but you could also consider a I Joist, stick built structure with cellulose fibre.

Speed is similar, just the time for the CPS and SIPs is in a factory and not on site.

CPS (as I understand what you mean by it) and I Joist are pretty similar in costs, performance and time, but for me I Joist just edges it (but I'm biased).

Thanks for this, plenty to think about! What is an I Joist kit? Can you point me in the direction of a supplier so I can find out more? It’s a house for us, and warmth and comfort and definitely high on the list of priorities. Thanks 

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19 minutes ago, AnnaKH said:

Thanks for this, plenty to think about! What is an I Joist kit? Can you point me in the direction of a supplier so I can find out more? It’s a house for us, and warmth and comfort and definitely high on the list of priorities. Thanks 

 

Hmm, Touchwood Homes are well known for offering this and did have a great website showing lots of examples, but I notice they've let their website expire. I think they are still active on Facebook, but that doesn't hold the same info, so you'd need to contact them.

 

Cullen Timber Design (who design & engineer Touchwood's frames) have a little info. www.cullentimberdesign.com

 

In short, CTD can prepare a cutting list of the frame and send it to James Jones I-Joists and the pre-cut frame then turns up on site on the back of an artic, ready to be assembled in line with the very comprehensive CTD drawings.

 

A competent carpentry team could easily put the frame together. The benefit of Toucwood's involvement is if you are wanting to achieve extremely high air tightness (above PassivHaus), they have some processes, especially with the outer sheathing, that others would not be aware of.

Edited by IanR
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1 hour ago, AnnaKH said:

It’s a house for us, and warmth and comfort and definitely high on the list of priorities

That is purely a case of having a powerful heating system.

 

1 hour ago, IanR said:

How high on your priorities is low heat loss and comfort

This is about careful and sensible design from the start.  And before you know it, people will tell you all they know about 'thermal mass'.

Edited by SteamyTea
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1 minute ago, SteamyTea said:

That is purely a case of having a powerful heating system.

 

I think it's more about low heat loss and "correct" ventilation.

Comfort to me is stable temperatures.

 

Higher heat loss and "powerful" heating is more likely to lead to temperature gradients through the house (as you move away from the emitter) and cycling in time.

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2 minutes ago, IanR said:

 

I think it's more about low heat loss and "correct" ventilation.

Comfort to me is stable temperatures.

 

Higher heat loss and "powerful" heating is more likely to lead to temperature gradients through the house (as you move away from the emitter) and cycling in time.

This is the whole point I am making.

 

It is easy to heat anything up, just pump energy into it.  Don't matter where the energy comes from, or what form, the definition of energy does not change.

What gets difficult is doing that is a manner that meets all the 'comfort' levels.

 

There is not an SI unit for comfort.

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