At the back of our garden I am planning to build a concrete pad as a base for a garden shed.
The ground rises a bit towards the back of the garden and we have had to excavate in order to level the ground.
Consequesntly the concrete pad will need a wall on 3 sides to support the earth behind it if you see what I mean.
The pad itselef will be about 8'by 6' which includes about a foot extra width for the small wall on the 3 sides (shed is 7' x 5'). The wall willl only be 4 bricks high.
To support the shed, I have read that no hardcore foundation is necessary and the concrete should be about 3 inches thick. However I would think that the wall will need a bit more support.
My qurestions are these; How should I approach this? Should I dig down a bit further 1 foot from the edge on the 3 sides and put extra concrete in there or will I be able to get away with 3 inches all over. Will I need any expansion joints in the pad as well. If I should put some in where should I put them.
This is my first attempt at doing this sort of thing and am quite looking forward to the challenge.
[T] I think that would be a good idea .. act like a sort of 'footing'? A lot of this sort of this is down to how compaced the sub ground is before you start. Any hard bits in the middle (compared with soft round the outside) could cause the pad to crack across the lump (like breaking a ceramic tile across a matchstick). I don't think the wall will impart any serious load on the pad. Not sure what load the soil might put on the wall though? Will you be able to make the pad slope toward the open face (for drainage).
Will I need any
[T] I didn't on a 20 x 10 base for my garage / workshop?
[T] Given the right conditions ..(ie not O or 40 deg C) it could be very rewarding / back breaking / frustrating / expensive ;-)
All the best ..
T i m
p.s. When tamping / floating off the surface make sure you don't kneel or touch the wet cement too much or you may get some nasty burns ..
p.p.s If you plan to put power in there (even if not now but possibly later) at least run a pipe of some sort from under the pad and up into a back corner or somewhere. Easier to poke a power cable through a tube than 3" of concrete!
At the back of our garden I am planning to build a concrete pad as a base for a garden shed.
The ground rises a bit towards the back of the garden and we have had to excavate in order to level the ground.
Consequesntly the concrete pad will need a wall on 3 sides to support the earth behind it if you see what I mean.
The pad itselef will be about 8'by 6' which includes about a foot extra width for the small wall on the 3 sides (shed is 7' x 5'). The wall willl only be 4 bricks high.
To support the shed, I have read that no hardcore foundation is necessary and the concrete should be about 3 inches thick. However I would think that the wall will need a bit more support.
My qurestions are these; How should I approach this? Should I dig down a bit further 1 foot from the edge on the 3 sides and put extra concrete in there or will I be able to get away with 3 inches all over. Will I need any expansion joints in the pad as well. If I should put some in where should I put them.
This is my first attempt at doing this sort of thing and am quite looking forward to the challenge.
I never heard of a wall standing without foundations. Why not just incorporate some stonework into the soil as a rockery? That should hold it. Digging down 18" for a concrete foundation will use 4 more bricks. And another 2 or 3 to accomodate the extra earth from the footing.
This is a retaining wall, and although the load on retaining walls is pretty heavy, yours will only be 4 bricks high. I would expect that a single layer of brick would be adequate for such a small thing. I would give the wall a foundation myself, not just rely on the pad to not move.
Since its outdoors with no heating it will freeze: I expect ordinary bricks would therefore deteriorate over time. Engineering bricks would last better, and since youre using so few of them theyd cost minimal extra. Someone may well disagree on that point.
I dont know what regulations exist around these things, but there might be some you'd want to comply with.
I had the opposite situation - i.e. the ground slopes a little downwards going away from the house. Rather than digging down at the house end, I elected to have the base one course of bricks above surrounding ground at the house end and four at the far end. Not wishing to see the ugly sides of the concrete, which could have been done by shuttering it with wood and pouring, I have bricks matching the house ones around the edge. It's the opposite to what you are doing, but the principle is the same.
The construction was done by levelling the area, and then digging out a trench about 250mm wide and about 300mm deep around the edge and filling with concrete.
This was allowed to cure for a couple of days and the wall was then built on top.
Two days later some hardcore was put into the base area and finally concrete poured and levelled.
The area is about 3mx3.5m and expansion joints weren't used. I'm not certain about the point at which that is required, but it wasn't for this size, which is larger than you are talking about. THere haven't been any problems with it.
The base depth should be OK, but the wall should have some foundation to support it.
I would dig a bit further down. I would also arrange for the top of the base to be a bit above the ground at the front of the garden rather than strictly at ground level, even if only by 30mm or so. You may find that some water finds its way from the higher ground at the bottom onto the concrete. Having the plinth a shade above the surrounding lower ground will allow water to drain off. You don't really want the bearers of the shed sitting in water. To this end, make sure that the base is either dead level or has a very fractional slope towards the low end. You can level the shed itself if necessary by using strips of wood on top of the bearers.
Some other things to consider:
- It's probably worth renting a concrete mixer for the base concrete. Even for this relatively small area, it's a lot of concrete and if you can mix and pour it all relatively quickly, the result will be better
- When you put down the timber bearers for the shed, it's worth putting strips of DPC material under them on the concrete (will stop dampness that soaks through the concrete from reaching the wood), and above them to completely isolate the shed base.
- It may be worth having the base slightly larger where the wall is so that there is a gap of say 100-150mm between it and the shed walls. This will allow getting a roller on a stick down there so that you can treat the walls with preservative in later years.
You didn't say in your first post that it was going to be a female shed. That alters things considerably as they are likely to be used by the women in the family and as such subject to major mood swings and various other unmentionable practices that in male sheds are normally shed.
She-eds require enormous amounts of support, not least emotionally.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.