engineering bricks?

[diy001]

I may be building my first ever exention and would like to run over a few questions with you guys. Hope you can help.

I already have a extention on the back living room, i want you extend the kitchen to match it.
How many courses of brick work should there be below external floor level? Do i need to use engineering bricks below external ground level?

 

[jeds]

The standard is to build a couple of courses of brick below ground level to allow for ground shrinkage and settlement. You might build one or two more to avoid cutting blocks. The rest would be blocks down to the foundation. How many courses depends how deep your foundation is, but you don't want to be building blockwork in the bottom of a very deep trench so if it starts getting too deep you would trench fill.

The bricks and blocks must be rated for use below ground.

 

[diy001]

Just to clarify im building this extention for my own house ,its my first ever building project and as im looking to hopfully became a builder i'm hopeing to gain ad much experiance as possible and not looking to cut any corners.

Jeds thanks for the reply, i have been told that the trenches would be approx 1mtr deep. Would it be best
1, to fill it up with concrete+ 3course eng brick+ (cavity) 1 block up to dpc
2, to fill it up with concrete + 3course eng brick + (Cavity) 3course eng brick up to dpc
3, or fill foundations with blocks + 2/3 course of eng bricks up 2 dpc.

 

[noseall]

It is far better to mass fill with concrete to within at least 7 courses of brick below dpc.

This is so that you can accommodate any bottle gullies next to the external wall.

A typical construction would consist of two courses of 7n dense concrete blocks and 1 course of class b semi engineering on the inner skin and 1 course of blocks plus 4 courses of bricks on the outer skin.

Also by having a single course of bricks on the inner skin, allows you to knock off the top course of bricks (at door opening detail) when it comes to screeding up to the door threshold at a later date.

 

[diy001]

Thanks for the reply noseall, your reason for 1 block and 4 brick on outer wall is so only brickwork is seen on the outside right?
Or is there another structural reason for having 2block+1 brick on inner whilst having 1 block + 4brick in outer.
also the caity in this wall would be filled with concrete right?

Sorry for all the dumb sounding questions, and believe me theres many of them yet to be asked

 

[noseall]

your reason for 1 block and 4 brick on outer wall is so only brickwork is seen on the outside right?

Correct, purely cosmetic. showing 4 bricks allows tolerance in ground levels particularly where you drop the ground for falls to gullies when fitting hard paving like slabs etc.

also the cavity in this wall would be filled with concrete right?

The cavity should be filled to within 225mm of the dpc. Do not fill it any higher.

 

[diy001]

noseall what advice would you have for the wall tie kit? the extention wall will be attached to a existing wall, is it necessary to bolt a tie kit and use ties to attach the walls together?
i'm aure about 10years ago when i had my living room extended the builder never used any tie kit, except the cavity ties. please advise

 

[wavetrain]

I have heard there is a new type of brick called the 'Civil Engineering Brick', it is a lot easier to lay apparently.

 

[noseall]

noseall what advice would you have for the wall tie kit? the extention wall will be attached to a existing wall, is it necessary to bolt a tie kit and use ties to attach the walls together?
i'mm aure about 10years ago when i had my living room extended the builder never used any tie kit, except the cavity ties. please advise

You need to either mechanically tie or block tie or tooth-in.

Proprietary wall ties or starter kits are widely used when connecting buildings together. They are easy to install and are more versatile than say having to block tie or tooth-in.

Not tying in at all sounds bonkers.

 

[diy001]

thanks noseall, my humble appologies for all the dumb questions. Im learning