Has my shed base been laid correctly?

Furts

James_Pinder wrote: »

I assume by this you would recommend that I lay a concrete base instead?



As much as I hate reading the word foolish when it is aimed at me, I know this is true. I've learned this the hard way this time. And I thank you for your advice (and everybody else's). I don't think I will pursue this with the builder as I have nothing substantial to back me up. I think once the weather is a bit nicer I shall get out there and have a go at it myself. In the mean time i'll do a bit of research online so I will have more of an idea of what I am doing. I won't try and take the shed apart as previously mentioned. I'm sure a few long timbers and a couple of friends round should be able to help me move it.

I can't just leave it and hope for the best as this could end up costing me more in the long run as the next step is to get electrics out there. I need it to be perfect before this happens.

Whatever you do think carefully about your 600x600 slabs. No idea what thickness yours are but usual ones are 50mm deep. No way can you re-lay those without a second pair of hands, and even then they are swines to work with if you are not used to them. If you buy new ones, make sure they are hydraulically pressed concrete (not vibrated), and make sure they are not riven, or patterned. Aim for 450x450, and some of these slabs are suitable and come at 50mm deep - though 35 -40mm should be OK for your job.

James_Pinder

Furts wrote: »

Whatever you do think carefully about your 600x600 slabs. No idea what thickness yours are but usual ones are 50mm deep. No way can you re-lay those without a second pair of hands, and even then they are swines to work with if you are not used to them. If you buy new ones, make sure they are hydraulically pressed concrete (not vibrated), and make sure they are not riven, or patterned. Aim for 450x450, and some of these slabs are suitable and come at 50mm deep - though 35 -40mm should be OK for your job.

I've measured them this evening and they are 38mm thick. The best description I can find (comparing to similar ones I have found online) is 'pimpled'. So going by your advice if I want to avoid further issues I should not use these when redoing the work. I will keep your recommendation in mind for the 450x450 slabs but if I wanted to keep costs down would a concrete slab base be ok or would it be better to stay with slabs? I'm assuming either option I could use the old slabs as a sub-base?

Furts

James_Pinder wrote: »

I've measured them this evening and they are 38mm thick. The best description I can find (comparing to similar ones I have found online) is 'pimpled'. So going by your advice if I want to avoid further issues I should not use these when redoing the work. I will keep your recommendation in mind for the 450x450 slabs but if I wanted to keep costs down would a concrete slab base be ok or would it be better to stay with slabs? I'm assuming either option I could use the old slabs as a sub-base?

Sounds like the slabs are decent quality, albeit somewhat thin. The money saving way forward is straightforward now, but includes some "buts". If you are happy dealing with the weight and size of these slabs (get a mate to help you) then re-use them as your new finished base. However it is vital the slabs are fully bedded when laid otherwise you risk cracking when laying, or when the shed is on them.

seatbeltnoob

I personally would make a wood frame, around the base, spirit level it and then fill it with concrete. Slabs will never be 100% level.

Begsey

I grabbed free slabs from someone for a shed base previously, a mix of slabs of different sizes, thinking I'd save a few bob.
It was a disaster, so ended up going with a concrete slab.
Someone I knew happened to have a cement mixer on hire, which was a bonus. Just done as suggested. Left the slabs in place, built up a 4in frame around it all and concreted it.

FreeBear

Begsey wrote: »

Someone I knew happened to have a cement mixer on hire, which was a bonus.

Well.... It is possible to mix sufficient concrete by hand.... Did it myself with a wheelbarrow, bucket, rake & spade. Tip the first bucket of ballast in the wheelbarrow, sprinkle about a fifth bucket of cement over. Mix with the rake & spade. Add a second bucket of ballast & repeat, and so on until five buckets of ballast has been mixed. If it has been raining for the last few days, there shouldn't be any need to add water to the mix, and if you do, half a bucket will be plenty.

Should take about a day to mix one and a half bulk bags of ballast/cement and cost around £130. Or you could get a readymix delivered for about twice the price.

seatbeltnoob

FreeBear wrote: »

Well.... It is possible to mix sufficient concrete by hand.... Did it myself with a wheelbarrow, bucket, rake & spade. Tip the first bucket of ballast in the wheelbarrow, sprinkle about a fifth bucket of cement over. Mix with the rake & spade. Add a second bucket of ballast & repeat, and so on until five buckets of ballast has been mixed. If it has been raining for the last few days, there shouldn't be any need to add water to the mix, and if you do, half a bucket will be plenty.

Should take about a day to mix one and a half bulk bags of ballast/cement and cost around £130. Or you could get a readymix delivered for about twice the price.

I would highly recommend drill attachment paddle at the very least. https://www.toolstation.com/shop/p92433


you can get more expensive ones that are longer and wider and even get dedicated concrete mixing drills. But for one of use I would made do with this £2.50 attachment


The sand, cement and hardcore needs to be mixed in very well to make a solid concrete block. The better it is mixed the stronger the end result will be. So I like to mix it very thoroughly, rather than giving it a few stirs with a spade.



It makes life a lot easier, otherwise it's a very long process to hand mix and backbreaking work.

DCFC79

OP did you get anywhere ?