Extension close to existing garage

[diy_darren]

I am considering building an extension at the rear of my house, but I have concerns attaching it to the single skinned garage wall because it doesn't have decent foundations.

Although the plan is for a single story extension I would like it to be able to support two stories incase it's required in the future. If I chose to build a new brick/block wall alongside the garage, how close could it be to the existing wall?

[code:1]|=============|
| |--------|
| EXTENSION | GARAGE |
| | |
|=============| |
| HOUSE | |
| | |
[/code:1]

 

[ColJack]

depending on the size of the wall joined to the garage, you might be able to "underpin" one corner of it with the new foundations..


( BTW, I'm a sparky so am only offering an educated guess... )

 

[Fluffster]

Building control are going to insist on footings at least 1m deep all round whether it is single or double storey I am afraid.
In terms of how close to the wall can you go you are looking at footings 600mm wide so divide by 2 and take away half the block size you intend on using.
Pete

 

[^woody^]

The garage is not a structural part of the proposed extension - it is merely enclosing it. There is no need for the garage to be underpinned, only requirement is that it is insulated adequately where it forms part of the extension

If you want a second storey later, then you would just span a lintel from the house to the external wall of the extension at ceiling level and build off that

 

[diy_darren]

only requirement is that it is insulated adequately where it forms part of the extension

This is insulation in addition to a layer of plasterboard and wool?

If you want a second storey later, then you would just span a lintel from the house to the external wall of the extension at ceiling level and build off that

I see, so a 5m lintel would provide a solid base for building another story.

This sounds a more economical way considering it's 5m less brick/block to construct.

Is there any advantage in rebuilding that one edge of the garage wall as brick/block aside from my feeling of completeness for the new room

 

[ColJack]

i didn't mean that the garage needed underpinning.

I was just sugesting that if the foundations needed to be a certain depth and width, and that if the garage wall interfered with this then it could be poured under the garage wall / foundation to acieve the desired depth / width?

no?

the alternative would be to demolish the back corner of the garage and dig up it's foundation and pour the new one then re-instate the corner of the garage as part of the extension?

 

[^woody^]

5m is too long for a lintel and at that length you will require a steel beam

How you insulate is up to you, either a timber frame or drylined are the common ways. I assume you will want plaster on the inside whatever you choose.

There is no point in demolishing somehting that can stay up. But it's up to you