ICF vs TF vs Brick + Block

[jayc89]

Getting to the point of our extension where I can start looking at construction methods and getting estimates. I haven't really narrowed it down from brick/block, ICF and TF yet. The extension's approx. 120sqm in total. From the estimates I have had;

 

- ICF (EPS) supply only is coming in at around £15,000 minus conc. (0.18 u-value)

- TF approx. £40,000, turn-key (0.14 u-value). This also includes joists and roof (unfinished)

- Brick/Block approx. £15,000 minus facing bricks (EPS beads, 0.18 u-value)

 

I'd love to say I had the time to go ICF and build to myself (how hard can massive lego blocks be, after all) but in reality I don't have that time given I'll be doing the groundwork myself too.

 

On the face of it, TF seems a good shout, especially given its construction time. My concern is that there's still a single skin of brickwork to erect on the exterior, so additional cost there. Probably £50,000 all in?

 

I suspect Brick/Block, inc joists and roof wood work would still work out slightly cheaper, but would take longer to erect. 

 

Are there any other benefits for TF over B+B?

Edited July 14, 2022 by jayc89

[Russell griffiths]

Have you had building regs passed yet, and if so at what u value for the walls, as the regs have changed and you need a better u value know if you haven’t already got it passed. 

[jayc89]

2 hours ago, Russell griffiths said:

Have you had building regs passed yet, and if so at what u value for the walls, as the regs have changed and you need a better u value know if you haven’t already got it passed. 

 

No, because we haven't decided on a construction method yet. Although I was under the impression extensions (L1B) needs to achieve a wall u-value of 0.18 now, is that not correct?

[Russell griffiths]

43 minutes ago, jayc89 said:

 

No, because we haven't decided on a construction method yet. Although I was under the impression extensions (L1B) needs to achieve a wall u-value of 0.18 now, is that not correct?

I’ve no idea what they have changed to, I just wanted you to be aware. 

[Indy]

U-values:
Floor: 0.18
Walls: 0.18
Roof: 0.15

 

Link to the doc here - https://www.gov.uk/guidance/building-regulations-and-approved-documents-index#approved-documents

[JohnMo]

But why would you want basic BR insulation standards with energy prices the way they are and heading.  Insulation costs you once, heating bills cost forever.

 

Wouldn't worry about the building time, as once everything is place there is not much difference to get a house you can live in, most important bit is to get a builder you want to work with, then use what they are used too.  No paid for learning curve.  Getting wind and water tight is about 1/3 of the job.

 

I did ICF, because I built myself and suited me, its timber and stone slip clad.  Other have done stick build timber others block work

 

Timber frame will normally have a brickwork or block outer skin.

[jayc89]

Just now, JohnMo said:

But why would you want basic BR insulation standards with energy prices the way they are and heading.  Insulation costs you once, heating bills cost forever.

 

Wouldn't worry about the building time, as once everything is place there is not much difference to get a house you can live in, most important bit is to get a builder you want to work with, then use what they are used too.  No paid for learning curve.  Getting wind and water tight is about 1/3 of the job.

 

I did ICF, because I built myself and suited me, its timber and stone slip clad.  Other have done stick build timber others block work

 

Timber frame will normally have a brickwork or block outer skin.

 

I'm extending an 1850's house which, with the best will in the world, will never reach these levels (brickwork is such that EWI is a no go and we can't lose that much internal floor space to drop the u-value that far), so over indexing on the extension doesn't make much sense. 

 

Given 0.18 is not a million miles away from PH requirement of 0.15, I don't think it's that bad. Plus all three (ICF, TF and BB) where of similar u-values so gave a reasonable comparison. 

 

ICF is certainly attractive, I just don't think I have the time to do it myself (other than evenings/weekends, which SWMBO wouldn't be impressed with), and with BB being at a similar cost point, that's the way I'm currently leaning. 

[Mr Punter]

It sounds like you have excluded ICF.  Timber frame can pose some issues with differential movement against a masonry structure.  Brick / block may work for you.  Can you get a builder to do the whole thing up to weathertight?  Might save a load of hassle.