Which block to use

[mcluma]

I'm planning (have spoken to the building inspector and he is ok) to build my two story extension in block work, goes quick and is solid, and, the outside wall is going to be rendered (hence the blocks)

I’m looking for a 3.6n block (these are according to the inspector enough)

So I’m looking for a block 440 * 215 * 300

What do you recommend
Tarmac - Toplite
Hanson – Thermalite

Or what else is there?

Thanks
Chris

 

[freddiemercurystwin]

Builders and Building Control I use always seem happy with Celcon Standard I specify. All much of a muchness tbh. Funny block size you've got going on there? Or typo?

 

[^woody^]

Aerated blocks are crap to render on, consider a concrete block for exterior instead

 

[mcluma]

Builders and Building Control I use always seem happy with Celcon Standard I specify. All much of a muchness tbh. Funny block size you've got going on there? Or typo?

I thought it was a standard block

 

[hotrod]

I thought it was a standard block

Not quite. A standard (if there is such a thing) block would be 450*215*100. Your 440mm probably is a typo and the 300mm could relate to a trench block size used for the substructure........... possibly ?

 

[wavetrain]

The footer on your posts reads: 'If you put your mind to it, you can accomplish anything'

Perhaps, but you have to put your mind to it first, so what U value does BC require this wall to achieve, and how will the wall achieve this U value using a 300mm thick block?

 

[mcluma]

On the inside we will use insulated plasterboard

There will be no cavity by using the 300mm thick blocks

 

[wavetrain]

You have not stated your required U value or given your U value calculation breakdown.

Can you provide these to the forum?

 

[NS215]

WHY are you doing it solid and not with a cavity?????????

 

[mcluma]

Goes much quicker, and more solid

 

[RonnyRaygun]

You don't need to use 300mm blocks. 200 or 215 will be fine.

Just ensure you've got enough internal insulation to satisfy building control.

You won't gain anything structurally or improve the U value of the wall significantly by using 300mm blocks compared to 200mm.

Total wall thickness of around 300mm including insulation is pretty standard.

 

[freddiemercurystwin]

Goes much quicker, and more solid

More solid than what?

That's gonna be one thick wall with its insulation.

 

[mcluma]

width is 300 then 40mm insulated plasterboard

which is not much more then with normal brick/block

100mm brick
100mm cavity
100mm brick

insulation value of the celcon standard is arround the 0.15W/m2k
which is ok - isn't

 

[wavetrain]

width is 300 then 40mm insulated plasterboard

which is not much more then with normal brick/block

100mm brick
100mm cavity
100mm brick

insulation value of the celcon standard is arround the 0.15W/m2k
which is ok - isn't

The insulation value of celcon standard is 0.15W/mk. not 0.15W/m2k.

You do not have a clue about R values and U value calculations, if you did, you would know that the R value of your 300mm block is 2. How are you going to achieve a U value of 0.2 for your wall with 40mm ins. plasterboard??

I advise you to employ someone suitable to design this build for you.

 

[freddiemercurystwin]

Steady on wavetrain, there are ways and means you know!

40mm insulated plasterboard will comply but won't get you anywhere near 0.15. Building control may ask for a 50mm cavity bwteen the blockwork and the insulation BTW.