The Brew Cabin

Posted: **Mon Apr 05, 2010 11:04 pm**

Hi

I'm hoping someone might be able to give me a few pointers on my workshop/garage base build.

I'm building a garage/workshop at home. Its going to be 3m x 10m and i'm going to have a 150mm concrete base poured over a DPM & reinforced with matabar.

To make things a little interesting i've got to built a retaining wall at one end for the concrete slab to be poured on top of.This will also be made from concrete and poured between some shuttering and again strengthend using some matabar.(pics should hopefully make it clear)

As the base is quite long (10m) and to make sure i'm getting it all level i've had to mark it out in sections which will also mean pouring it in sections, however i'm a bit confused as to how to set up the various divisions without puncturing the DPM?? at the moment i've not laid the DPM i've just staked the shuttering into the ground aand checked that are all level. Any ideas?

The existing base of the old shed, the new garage will be extended slightly as far as where the footings have been dug. The plan is to build a reinforced concrete wall up to the existing base level. Infill the gap between the existing base and the new wall, then pour the new concrete base/flooring on top of it.

The carport (which has come down)

First section started to be dug out

The section between the shutter and the gate is going to be dug out and block paved oce the concrete base has been finished

cheers

Matt

Posted: **Tue Apr 06, 2010 4:32 am**

this will help

Posted: **Tue Apr 06, 2010 8:56 am**

Yeah i've read that link but it doesn't really answer my question

Posted: **Tue Apr 06, 2010 11:45 am**

This page might be helpful to you.

I used the walls of the garage for supporting timbers, which in turn supported the shuttering

Posted: **Tue Apr 06, 2010 12:31 pm**

ah thats really useful thanks!!!!

So going on that it would seem the best way to do it would possibly be to edge the bottoms of the walls in some timber shuttering as well and then put the dividers between these rather than flush up against the wall, the dividers can be fixed to these rather than needing staking into the ground and therefore puncturing the DPM.
The timbers against the wall would then act as a sort of expansion joint as well i guess so the concrete base doesn't force against the bottom of the wall.

Posted: **Tue Apr 06, 2010 6:31 pm**

Mat i have a question. At the end of the building where the retaining wall is required you mentioned shuttering. Now i've looked at the pictures i would like to know how you are going about this.

Posted: **Tue Apr 06, 2010 9:16 pm**

irishpaving > i've got some large sheets of 18mm OSB and lots of 3"x2" so i plan on making some formwork which will sit in the footing trench i have dug. I'm thinking of making it about 350-400mm thick. The inner skin of the formwork will come up to the ground level of the base and the outer skin will come up a further 150mm (the depth of the base pour) so that when the final base is poured i can screed it to that level.

Obvioulsy the formwork will have plenty of lateral support to prevent it bursting/falling over from the weight of the concrete between it. I will have lengths of matabar between the 2 forms and i will leave some of this protruding from the wall pour so that it ties into the base pour.

hope that make sense

Posted: **Tue Apr 06, 2010 10:00 pm**

dont forget to put foam expansion strips against all of the walls before you pour.

Posted: **Tue Apr 06, 2010 10:08 pm**

why spoil such a nice dry stone wall by putting a concrete one beside it ??? At the very least i would place a foundation and use some nice bricks to compliment it, unless you can get some dry stone walling. Or set your concrete back and pit a skin of bricks etc; up the side of it. Don't use timber between your existing dry sone wall and slab, use fibre board, or simular.

Posted: **Tue Apr 06, 2010 10:41 pm**

ah sorry yes i should have said the i'm going to clad the concrete wall with some drystone bricks so that it all blends in and you don't see the concrete wall

i've got tonnes of the bloody stuff spare!!

rab1 > so would it be better to use these expansion strips against the wall rather than placing some wooden boards and then remove them once the base had set?

Posted: **Tue Apr 06, 2010 10:43 pm**

Would like to see the formwork just before the pour Matt

Another thought is if you need to run anything into the building before you cover the floor etc....

Posted: **Tue Apr 06, 2010 10:46 pm**

does the formwork sound like it will be ok?

i've already run 6mm 3 core swa cable out there, as i had power to the old shed previously. It's buried nice and deep below the surface

Posted: **Tue Apr 06, 2010 11:00 pm**

Personally i would use some braces on it. I always get worried when i hear the sterling name..

Posted: **Tue Apr 06, 2010 11:06 pm**

do you mean some timber lengths joining the 2 skins together? or some 45 degree stakes in the ground against the skin walls on the outside?

Posted: **Tue Apr 06, 2010 11:10 pm**

Sorry matt i keep thinking you are going up to the height of the existing wall.

But you will know if it needs 45 brace on it if it feels a bit weak... Which end are you starting the pour from or which way will the concrete come from.

The Brew Cabin

Long concrete garage/workshop base (10m) - Advice needed