SIPs quote

[Kevan Marshall]

Just had a quote for supply and erection of SIPs house, my house is 180sqm ground floor area with provision to convert loft 70sqm at later date, external walls 197mm SIP panels to give U value of 0.13 or 172mm SIP panels plus 25mm PIR internal insulation to give U value of 0.12, roof is of vaulted truss system with steels in to support and boarded out and insulated to 0.12, all supporting stud walls are supplied, posi joists are supplied for loft conversion and floor boarded out, all wall and roof locations made airtight and battened out for service void ready to plasterboard, all exterior areas made weather tight, all crane hire, delivery costs included, airtight test done after I fit windows, all paperwork done for building control, with quite a lot of structural support walls going in leaves me very few stud walls to put in after installation of screed floor, I am waiting on quotes from two other SIPs companies but does this seem a reasonable price at 100k?

 

kind regards,

Kevan.

[Russell griffiths]

What score do they say they will achieve with the airtightness test. 

[Nickfromwales]

18 hours ago, Kevan Marshall said:

Just had a quote for supply and erection of SIPs house, my house is 180sqm ground floor area with provision to convert loft 70sqm at later date, external walls 197mm SIP panels to give U value of 0.13 or 172mm SIP panels plus 25mm PIR internal insulation to give U value of 0.12, roof is of vaulted truss system with steels in to support and boarded out and insulated to 0.12, all supporting stud walls are supplied, posi joists are supplied for loft conversion and floor boarded out, all wall and roof locations made airtight and battened out for service void ready to plasterboard, all exterior areas made weather tight, all crane hire, delivery costs included, airtight test done after I fit windows, all paperwork done for building control, with quite a lot of structural support walls going in leaves me very few stud walls to put in after installation of screed floor, I am waiting on quotes from two other SIPs companies but does this seem a reasonable price at 100k?

 

kind regards,

Kevan.

Doesn’t sound terrible tbh, but I’m just not a fan of SIP’s vs a proper timber frame blown full of cellulose.

 

Have you read the small print twenty times? Usually you’ll be responsible for a lot of stuff and you need that costed out before you take one more step forward, so you have a high level project cost.

 

I was going to ask about the promised AT score, but I’m assuming 1.0ach or close to? 

[Kevan Marshall]

15 hours ago, Russell griffiths said:

What score do they say they will achieve with the airtightness test. 

They have told me AT shall be well within limits, as long as I install good quality triple glazing then it should be up into passive standard 

[Kevan Marshall]

3 hours ago, Nickfromwales said:

Doesn’t sound terrible tbh, but I’m just not a fan of SIP’s vs a proper timber frame blown full of cellulose.

 

Have you read the small print twenty times? Usually you’ll be responsible for a lot of stuff and you need that costed out before you take one more step forward, so you have a high level project cost.

 

I was going to ask about the promised AT score, but I’m assuming 1.0ach or close to? 

Yes, even on the quote they are 100% clear what they are responsible for and what I am responsible for, only thing I want to ensure is that window sizes as per drawing are within tolerance and if windows do not fit due to incorrect sizes then they shall be responsible, they assure me they have never had any issues before and windows/doors can be ordered during  kit manufacture 

kind regards,

Kevan.

[JohnMo]

8 hours ago, Kevan Marshall said:

only thing I want to ensure is that window sizes as per drawing are within tolerance

That is pretty easy for most builds. One caveat, you and everyone else are working to the same drawing revision. People change stuff, they assume because they know, and the architect knows, everyone does.

 

I had final sign off on all drawings for the build, once our building warrant was approved, no drawings got changed, no details where changed. But that isn't the case very often. So dot you eyes and cross you tees.

[Mr Punter]

16 minutes ago, JohnMo said:

That is pretty easy for most builds. One caveat, you and everyone else are working to the same drawing revision. People change stuff, they assume because they know, and the architect knows, everyone does.

 

I had final sign off on all drawings for the build, once our building warrant was approved, no drawings got changed, no details where changed. But that isn't the case very often. So dot you eyes and cross you tees.

 

+1

I changed a couple of door handings and although drawings were updated, the electricians worked from an old set of drawings we had sent out for quote purposes, so there was some messing to get light switches in the right place.

[Kevan Marshall]

1 hour ago, JohnMo said:

That is pretty easy for most builds. One caveat, you and everyone else are working to the same drawing revision. People change stuff, they assume because they know, and the architect knows, everyone does.

 

I had final sign off on all drawings for the build, once our building warrant was approved, no drawings got changed, no details where changed. But that isn't the case very often. So dot you eyes and cross you tees.

Thanks John,

I want to be strict on no changes, to be honest I have more confidence in my contractors than I do my Architect who is questioning everything, trying to change things and complicate everything, unfortunately I need him for getting everything signed off.

 

kind regards,

Kevan.

[Kevan Marshall]

1 hour ago, Mr Punter said:

 

+1

I changed a couple of door handings and although drawings were updated, the electricians worked from an old set of drawings we had sent out for quote purposes, so there was some messing to get light switches in the right place.

I spent a lot of my time looking at every detail as I had the attitude that if you change anything it costs money, I have also told the boss (wife) that, also went down the KISS route (keep it simple and stupid).

[SteamyTea]

18 hours ago, Kevan Marshall said:

They have told me AT shall be well within limits

Do they mean Building Regulation limits, which are pretty poor.

 

[Kevan Marshall]

2 hours ago, SteamyTea said:

Do they mean Building Regulation limits, which are pretty poor.

 

Well beyond that getting upto passive house standards 

[JohnMo]

13 hours ago, Kevan Marshall said:

Well beyond that getting upto passive house standards 

I would want a number, otherwise it's meaningless. Getting towards something is very open to interpretation, scoring 6m³/m² @ 50Pa is getting towards passivhaus (it's nowhere near) compared 10. You possibly thinking under 1.0, so there may or may not be a big gap of expectations?

[ProDave]

On 19/12/2025 at 23:52, Kevan Marshall said:

only thing I want to ensure is that window sizes as per drawing are within tolerance and if windows do not fit due to incorrect sizes then they shall be responsible

Regardless of any assurance, before ordering windows I would MEASURE the actual window openings as built.

 

I paid a local builder company to build and erect my frame, and then later paid them to supply and fit windows.  Even they did not trust they had built the openings to the drawing, and measured them before ordering windows.

[saveasteading]

46 minutes ago, ProDave said:

openings to the drawing,

A quality window contractor will minimise the gap, and the amount of filler/ foam needed to fill it. Even the best builder will have wobbles and variations in the opening, and that quality window contractor will insist on measuring. They will also use expanding tape to get a good closure that will move with the building , not squirt stuff in after.

[Kevan Marshall]

5 hours ago, JohnMo said:

I would want a number, otherwise it's meaningless. Getting towards something is very open to interpretation, scoring 6m³/m² @ 50Pa is getting towards passivhaus (it's nowhere near) compared 10. You possibly thinking under 1.0, so there may or may not be a big gap of expectations?

Hi John,

I shall ask the TF company what they can guarantee and ask for proof from previous builds

[Kevan Marshall]

3 hours ago, saveasteading said:

A quality window contractor will minimise the gap, and the amount of filler/ foam needed to fill it. Even the best builder will have wobbles and variations in the opening, and that quality window contractor will insist on measuring. They will also use expanding tape to get a good closure that will move with the building , not squirt stuff in after.

As soon as I get detailed drawings from TF company I’ll ask Window suppliers what their turn around shall be, if they install the walls it may take the TF company one week to install the roof, etc so that might help me for time

[Kevan Marshall]

4 hours ago, ProDave said:

Regardless of any assurance, before ordering windows I would MEASURE the actual window openings as built.

 

I paid a local builder company to build and erect my frame, and then later paid them to supply and fit windows.  Even they did not trust they had built the openings to the drawing, and measured them before ordering windows.

As soon as I get detailed drawings from TF company I’ll ask Window suppliers what their turn around shall be, if they install the walls it may take the TF company one week to install the roof, etc so that might help me for time

[Redbeard]

Add a good margin for error to the cited turn-round time. My last big-ish order was estimated at 8 weeks and took just under 14.