footing size / depth

Joined
30 Jan 2007
Messages
2,256
Reaction score
52
Location
West Midlands
Country
United Kingdom
hi, what width and depth do my footing need to be?


Im having a garage built that is a bit higher than normal (3.20 ceiling height)

Its been built out of concrete blocks and walls are only 1 course deep. However there will be a double skin wall along one wall where its a retaining wall (1 meter of soil)


The plans i have only show footing for double skin wall and not single. They show 750mm deep by 600 wide mass fill concrete

Do i need them that large still?
 
Sponsored Links
The mass filling is not for extra strength it is just to save you time, and therefore money, by not have to build footings up to the required height.

Provided you dug down enough a footing 200mm deep would be plenty strong.

As for your widths when you say one course deep do you mean a 4inch wall i.e. block on edge or 9inch block on the flat.

As a general rule of thumb the footing should be twice the width of the wall.
 
yes 4 inch thick wall. Apart from where its retaining 1 meter of soil where it will be two lots of 4" blocks filled with cement in the void.

So if i understand correct then!

I dont need the footings to be 600mm wide where the wall is going to be 1 brick thick (4") But i can get away with 250mm wide?

However the wall needs pillars every 2 meter or so, maybe it will just be easier to do the footings at 600mm wide rather than messing around making them wider at these points?
 
Matty,
Firstly, you can not go to 3.200mm ceiling height To comply with planning your maximum height to eaves is 2.500mm

Quote from Planning Portal

Outbuildings and garages to be single storey with maximum eaves height of 2.5 metres and maximum overall height of four metres with a dual pitched roof or three metres for any other roof.
End of quote.

Foundations to comply with building regs 1.000mm deep by minimum 450mm wide by 750mm trench fill concrete. Suggest 600mm wide where cavity wall is going. Local building control may want 600mm allround
old un.
 
Sponsored Links
Matty,
Firstly, you can not go to 3.200mm ceiling height To comply with planning your maximum height to eaves is 2.500mm

Quote from Planning Portal

Outbuildings and garages to be single storey with maximum eaves height of 2.5 metres and maximum overall height of four metres with a dual pitched roof or three metres for any other roof.
End of quote.

Foundations to comply with building regs 1.000mm deep by minimum 450mm wide by 750mm trench fill concrete. Suggest 600mm wide where cavity wall is going. Local building control may want 600mm allround
old un.


The plans have been drawn and passed showing a overal height of 3.6 meters. It has a flat roof but with a pitch roof hanging off the front and going over a porch.

I take it as the plans have been passed they cant change there mind on the height they approved? I hope not as i need the height inside the garage!

The foundations on the plans are as you have said for cavity wall type build, they dont show details for single brick. I guess i will just do as the plans suggest for cavity wall. i tried to speak to building regs about it but they didn't want to talk to me about it!
 
Matty, What I quoted you was for permitted devolvement, but from what you say, you made a planning application which was passed. If that is the case then build away.
Just to put you right on one other thing. A half brick wall is 100mm wide old money 4 ins. A one brick wall is 215mm wide, old money 9 ins.
Will come back to you with regard to height of half brick wall at 3.200mm. There is a rule that I can not remember.
old un.
 
o.k thanks.


So my wall is going to be 100mm thick in total but with pillars built every 1.8 meters i think it is on the plans.


Does that sound correct?
 
Generally, a foundation needs to be approximately 150mm beyond the wall faces each side.

So, a half brick wide wall (4") would require 400mm wide footings.

A full brick - 525mm.

A 300mm wide (cavity wall) - 600mm.

Most foundation widths however are usually determined by the size of the digger bucket available. :LOL:
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Back
Top