Mixing concrete and thermalite blocks within the same wall?

[kingandy2nd]

Hi all,

Cracking on with my extension now, and following advice from here I am using 7nm lightweight concrete fibolite blocks on the outer skin, and 3.6nm thermalite shield blocks on the inside.

The thermalites are nice and easy to lay, cut, etc but are very fragile and I've got loads of damaged ones (not sure the builder's merchant is all that gentle with the packs).

As one room will be a kitchen in the extension, is there any reason why I couldn't lay a course or two of the fibolite blocks on the inner skin at the height that kitchen wall cupboards will go in order that I have a nice solid block onto which to fix the cupboards?

I can't think of any obvious reason - but nice to defer to the knowledge of more experienced people in case I'm missing something.

Cheers
Andy

 

[23vc]

You’re not meant to due to different expansion rates and possibly other theoretical reasons, but if it was me I definitely would. If it’s going to be plasterboarded.
Plenty of openings in brick walls get blocked up (one random example of mixing masonry)

 

[^woody^]

The thermal properties will be different, so a condensation/mould risk. but more theoretical than actual

Just use suitable fixings.

If the blocks are broken in the pack, complain to the merchants. If its your handling, be more careful, but they should not be breaking that easily.

 

[kingandy2nd]

The thermal properties will be different, so a condensation/mould risk. but more theoretical than actual

Just use suitable fixings.

If the blocks are broken in the pack, complain to the merchants. If its your handling, be more careful, but they should not be breaking that easily.

With regards to the broken blocks, it's as I take them out of the pack - mostly corners, that a damaged/chipped to varying degree so most are usable but it just shows the fragile nature of them.

Also within the different packs of thermalites there is serious variation in the quality of the surface - I will take a picture to show what I mean.

In a lot of these things I know you have to allow for some wastage, but I'm not sure what's considered reasonable and what isn't.

 

[kingandy2nd]

I'd say about 20% of the thermalites are like this.

And they vary in face quality quite a lot - both blocks taken out of separate packs of thermalite - all with the branded plastic wrapping so confident they're all the same type of block.

This only problem for me as I have a garage wall which will be on show, so trying to get the 'nicer' thermalites to use there.

 

[^woody^]

Are they seconds?

Normally these blocks have dead neat edges, often several are actually stuck together, and they are in a nice wrapped cube block.

 

[23vc]

Agree the ones in the top pic look cr@p and nothing like what new blocks should look like.

 

[kingandy2nd]

Are they seconds?

Normally these blocks have dead neat edges, often several are actually stuck together, and they are in a nice wrapped cube block.

Agree the ones in the top pic look cr@p and nothing like what new blocks should look like.

Nope, not seconds - as least not what I ordered.

All wrapped up on delivery for me, nothing to indicate they should be seconds.

The packs were stacked 3 high on my lawn which isn’t particularly even when delivered which has caused a big of movement in the packs, and caused some of the chips I guess.

Worth contacting Thermalite for quality control?