Foundation for a brick shed

[Shinogi]

Right, the trenches are all dug down to 500mm and I'm ready to mix my own concrete for the foundations but I'm confused on what ratio to use for the mix. Is it 1:2:4 or 1:3:6 or am I completely wrong?

What would be the best mix ratio to use so I can order my stuff

 

[Shinogi]

Foundations all done, thanks for everyones advice.

Just digging out the center ready for the hardcore to go in. I'll have some heavy weight in the shed like my weight bench and a couple of arcade machines. I have two questions if someone could answer them for me.

1, Am I right in thinking I need 150mm of Type 1 hardcore as the base

2, do I have to dig down to the clay, which would be deeper than 150mm, or do I just dig to around 150mm as long as the soil is firm?

Thank you

 

[pinenot]

For a shed I wouldn't be to particular, just make sure there's no organic matter in what's left and you'll be fine. I50mm hardcore with 50mm sand blinding on top is general...pinenot

 

[Shinogi]

Thank you

 

[fmck]

I used rubble. The remains of my chimney previously removed for my loft conversion shown on projects. Just a binder of sand compacted on top.

You should post pics and a diary on projects. I did it as I said for my loft and its nice to have a record to look back on. Doing it with my garden shed project at the moment.

 

[Shinogi]

I've taken pictures along the way and you are right, it's amazing looking back and actually seeing how much work you've actually done.

 

[Shinogi]

I've dug the center out now ready but we seem to be getting spurts of rain which is making the ground damp. Even though it made it easier to dig up the remaining corner today, is it best if I cover the ground up until I can get the compacted hardcore in there or does it not matter?

Untitled

• Shinogi
• 13 Jun 2013
• 1

Also, the sand blinding, is it sharp sand or builders sand used for that? I have a tonne of sharp left from the footings andd wondered if I could use that up?

Thanks

 

[Shinogi]

I'm ready to build this up now this year but I'm not 100% sure what concrete blocks to use.

My plan is to use solid medium density 3.6n concrete blocks for both the outer and inner leaf of the wall. Possibly render or seal and paint the exterior wall. Would I be better using solid dense 7.3n blocks for the outer leaf or is that over doing it?

If it makes any difference, I will be using bricks for the front wall, which is the only wall I will see, which will have to mesh in to the blocks around the corners of the outer leaf.

Any advice will be appreciated, thank you.

 

[pinenot]

Personally I would go by cost alone, as in your case it doesn't matter which compressive strength you use, as it's only a single story building. The only other considerations you might like to look at are weight/block and face smoothness, if you want to paint them, the latter can be bought as single paint face grade, or double paint face grade, so think cost, weight of handling and finish and you will do well.
If you decide to render the blocks and your using facing brick to the front elevation, remember to build the opposite elevation to this 40 mm or so narrower, to accommodate the thickness of the render, in fact you might want to make the returns of the facing brick elevation into mock pillars os something...pinenot

 

[Shinogi]

Thank you pinenot, you've been most helpful throughout this project so thank you.

I'll just paint the blocks then as I'm not really after it looking spectacular as I won't see the 3 block walls anyway. I'll stick with the 3.6n blocks then for both leaves and paint up the outer leaf. Would I need a sealer or would the paint suffice?

 

[pinenot]

A Good quality exterior grade paint will both seal and waterproof. I used to use one that was an aliphatic polymer, monolithic based and was self cleaning, by way of tiny particles flaking off over time, it had a 25 year guarantee mind you...pinenot

 

[Shinogi]

I'll get some stuff ordered then, thanks again

 

[themiddleagedun]

Personally I would use the 7n blocks, though others would disagree I find they give a much stronger job,
If you're rendering & painting the blockwork, the costs will end up similar to brickwork, but with more maintence...

 

[Shinogi]

That's why I thought of 7n blocks for their strength so posted on here asking the question to see if they were needed. I'll see what the weight differences are between the two but I'll be using 3.6n's for the inner leaf and just painting the outer leaf to save time and costs. The price difference between the two blocks is the same.

 

[Shinogi]

The building side of it is pretty much done now, I just need to sort out the roof but trying to figure out what pitch I need on the roof is doing my head in. Could someone offer me some advice please?

The joists are going to be 5m (taking weight over 4.16m) and online tables tell me they need to be 220x75mm. I need to sort out the wall plates for the joists but how much higher would the highest side need to be to allow for a decent enough slope? I have 82mm to play with, due to the height restriction, which includes the joists, 18mm OSB and EPDM. Would a 52mm fall be enough?

The plan is for a flat roof with EPDM rubber covering.