New Build Timber Frame Wall Build Up

[Iceverge]

Are you planning on stick building the frame? 

 

Have you considered blown insulation AKA cellulose. 

 

There's lots going for it. 

[Gballam]

2 hours ago, Iceverge said:

Are you planning on stick building the frame? 

 

Have you considered blown insulation AKA cellulose. 

 

There's lots going for it. 

No it will be open panels. Preferred the rockwool approach as we can do that ourselves

[Nickfromwales]

10 minutes ago, Gballam said:

No it will be open panels. Preferred the rockwool approach as we can do that ourselves

Getting the cellulose pumped isn’t cheap either. It’s good, but rockwool + DIY will be more cost effective.

[saveasteading]

21 hours ago, Nickfromwales said:

avoid a cold-ventilated sub floor like the plague,

And 450mm isn't enough to justify beam and block.

The very clear difference is that below a slab you can have ground, (which insulates) or insulation, whereas below beams you have a draught.

 

[Gus Potter]

6 hours ago, saveasteading said:

The very clear difference is that below a slab you can have ground, (which insulates) or insulation, whereas below beams you have a draught.

Experience speaks. Agree, a ground bearing slab will benefit the overall u value calcs. 

[Iceverge]

10 hours ago, Nickfromwales said:

Getting the cellulose pumped isn’t cheap either. It’s good, but rockwool + DIY will be more cost effective.

 

What's the UK price now?  It's 4-5 years since I priced it here at €150/m3. 

 

Fitting mineral wool isn't particularly nice as jobs but it's very doable. Has anyone done blown mineral wool? 

 

[Dave Jones]

out of curiosity why are you going down the #TF route ?

 

Are you expecting to be fully complete in 3 months and move in ?

 

speed seems to be the only factor in justifying its double the cost of a normal build. 

[Gballam]

10 minutes ago, Dave Jones said:

out of curiosity why are you going down the #TF route ?

 

Are you expecting to be fully complete in 3 months and move in ?

 

speed seems to be the only factor in justifying its double the cost of a normal build. 

Not managed a self build before and am copy pasting the structure of house my parents and then brother built. Seems like a good way of getting a well-insulated house especially as we want to be doing bits ourselves 

[ADLIan]

8 hours ago, Gus Potter said:

Experience speaks. Agree, a ground bearing slab will benefit the overall u value calcs. 

For floors with the same footprint, edge conditions and say 50mm of PUR the solid floor will offer a slightly better U-value, but perhaps only by 0.01 W/m2K, compared to B&B suspended floor. With 150mm+ of PUR there's even less of a difference - unless you start looking at the 3rd decimal place or beyond.

[saveasteading]

25 minutes ago, ADLIan said:

better U-value, but perhaps only by 0.01 W/m2K,

I haven't got figures to hand, but the ground itself adds much more than that. The effect of the draught would need complex calcs and isn't considered in standard published figures that I have seen.

 

Anyway that is just one consideration. 

For beam and block:

useful on steep slopes.

Can be manhandled to tricky areas.

Not weather dependent.

Against: cost

 

Insulation can be dealt with separately.

 

 

[Nickfromwales]

1 hour ago, Dave Jones said:

out of curiosity why are you going down the #TF route ?

 

Are you expecting to be fully complete in 3 months and move in ?

 

speed seems to be the only factor in justifying its double the cost of a normal build. 

Not if you’re renting to build. 

[ADLIan]

The BS that covers the calculation of ground floor U-values includes an assessment of the sub floor ventilation in suspended floors

[stu w]

On 08/04/2026 at 21:50, Iceverge said:

 

I assume you put battens inside the pir layer? 75*25?

 

Did you have any issues with keeping them straight to hang the plasterboard? 

I run plywood down in my workshop and doubled up, very strong and remains nice and straight.

Certainly not the cheapest method but works well 

[Nickfromwales]

1 hour ago, stu w said:

I run plywood down in my workshop and doubled up, very strong and remains nice and straight.

Certainly not the cheapest method but works well 

Glued too?

[Iceverge]

Having used pumped insulation in the house attic and mineral wool batts in the garage I would happily say it's one of the best things I have done with the house. No itchy and scratchy show. 

 

I think @Gone West priced supafil when doing your house. Any idea of the cost installed? 

 

 

If you could find a machine to blow this behind a clear membrane you would have a cheap solution. 

 

 

 

 

[Nickfromwales]

44 minutes ago, Iceverge said:

Having used pumped insulation in the house attic and mineral wool batts in the garage I would happily say it's one of the best things I have done with the house. No itchy and scratchy show. 

 

I think @Gone West priced supafil when doing your house. Any idea of the cost installed? 

 

 

If you could find a machine to blow this behind a clear membrane you would have a cheap solution. 

 

 

 

 

Gordon Lewis came to site for 2 days, with a +1 in the van feeding the machine, and did a huge amount of work tbf. 
 

@Gballam PM me if you want his details, and what he charged, but he’s a lot cheaper than you may think. 
 

FYI he doesn’t supply, he estimates the volume and you order direct from PYC, then he just turns up labour only and pumps the stuff in. He allows for taping up the membranes back to airtight standard, and supplies the tape. 

[stu w]

17 hours ago, Nickfromwales said:

Glued too?

Yes, everything gets a good coat of D4 🙂