Can I use engineering bricks above solid concreate blocks for below DPC internal cavity?

[David H]

Hi,

I am attempting to complete most of the work on my extension myself. It's going good so far, foundations dug, poured and just building cavity up to damp in prep for the oversite. Its brick and block construction and it's 8 courses between the foundations and DPM.I am happy that the outer cavity will just be 8 courses of F2/S2 bricks but  for the inner cavity I plan to lay 2 courses of solid concrete blocks  and 2 courses of engineering bricks. Is this acceptable or do I need to buy Dense Concrete Common Bricks Grey 215mm x 100mm x 65mm  to use for the top 2 courses above the concrete blocks (to make up to 8 brick courses)?

 

Concrete commons don't seem to be available near me and I have some engineering bricks spare.

 

Thanks,

 

David

[Russell griffiths]

Use the bricks no problem, as long as you keep your courses level so ties work. 

[David H]

Thanks, I didn't think it would be an issue but thought I should check

[epsilonGreedy]

There are engineering bricks of varying quality out there, the default blue engineering brick from my BM has 3 oversize vertical holes running right through the brick, as a percentage they might be 30% air. A solid concrete brick (my brickie called them brickets) feels more substantial, having said that I received one pack of concrete bricks that rusted. It was later explained to me that these are made with a cheap clay with a ferrous content.

[Faz]

You want 7.3N concrete coursing blocks mate (brickettes) for the inner cavity wall below splash. Better and cheaper.

 

You can use 3.6N above as required.

[David H]

Thanks for the responses. I will go with the coursing blocks then. Not sure if I can post links but I think these are what I need and they seem to be able to deliver to my postcode:-

Dense Concrete Common Brick Grey 215mm x 100mm x 65mm – JMD Building & DIY Supplies (jmdbuildingsupplies.co.uk)

 

The description on the site:-

Coursing bricks can be used in all type of construction and in conjunction with dense aggregate blocks. 

 

 

[Faz]

Those look fine mate and the pricing isn't bad either for small orders.  Once above damp you can drop to 3.6N if you want but with coursing blocks it doesn't make any difference really - buy whatever is cheaper!

[epsilonGreedy]

35 minutes ago, Faz said:

Those look fine mate and the pricing isn't bad either for small orders.

 

 

Yes they do look good, it is the darker ones that tend to have the rubbish in their mix.

Edited March 2, 2021 by epsilonGreedy

[David H]

Thanks all, I have ordered them. It's a worry when the website pops up a message that they are too busy to answer phone calls even before you have ordered!