DIY Doctor

Trench block & tying in

Postby magictorch » Mon Apr 13, 2009 3:37 pm


I am building a single storey extension to the side of our house. The footings are in and the brickie is a no show. After weeks of promises I have decided to crack on myself. I have researched into using trench blocks as opposed to standard blocks (which are already on site). The face brick work on the existing house goes down to the original foundations which i have matched with my new extension foundations.

I understand how to tooth in my bricks above ground level.

Do I need to tooth in the new trench blocks or block bricks up to the DPC level?
If so how is this done?
I have linked to an image as an explanation. The little blue paint mark indicates where my existing DPC is.


Thanks in advance
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Simply Build It

Postby stoneyboy » Sat Apr 18, 2009 3:05 pm

Keying in below ground level is done the same as above so you need to cut out bricks to allow the blocks to be inserted into the existing wall (two holes should do.
You do need to look carefull at the DPC location - your photograph seem to show a stepped DPC.
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Postby elwood » Sat Apr 18, 2009 8:26 pm


Use fur fix profiles from bottom to top with in regs
and far more quicker and less mess.

Also advise get your self a reliable tradesman

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Postby Andy Fielding » Tue Apr 21, 2009 8:25 pm

I too am doing an extension and was told you dont need to tie in below dpc and you can quite rightly use Furfix or equivalent above DPC. Do a search on google for crocodile 2000 wall starter. sold by Buildbase and various others, got mine cheap on Ebay. States on pack not to bridge it accross DPC but doesn't say it has to be used below DPC. Make sure you put Lintels over the top of that soil pipe where it passes through the footings.
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