Shed Base?

stevec59 · 13 Apr 2010

My shed should be delivered Thurs this week, still haven't got a base but I want to put preservative on it before I goes together anyway.

I was going to go for a concrete base (shed is 8 x 10), but this is going to cost a fair bit, I had someone come around on Saturday and suggested using a dry mix @ 2" and paving slabs as that is what they do 95% of the time, my only concern is, a concrete base is 1 big lump of concrete @4" thick, not lightly to move etc, I did mention this to the builder and he said that a dry mix won't move.

Am I just as well going for a dry mix with slabs?

Also, I don't really understand a dry mix, from what I can work out its sharp sand and cement (no water), what does the cement do?

Thanks

Steve

Deluks · 13 Apr 2010

Maybe he meant compacted MOT, concrete should be used with water, always.
Compacted ground and slabs are ok for smaller sheds but one your size won't be easy to move once it's erected, and you don't want dips to start appearing. It probably cost a few hundred quid and deserves a decent base with some airflow beneath.
You could just as easy use concrete blocks with 4" fence posts on top. A post every 18" with 3 blocks supporting ends and centre.

Are there any readymix companies in your area?

Thermo · 13 Apr 2010

he proabaly meant using a lean dry mix of concrete to bed some slabs on. cheap crap way of doing it. doesnt last and looks pants. all our sheds go on a concrete base, with dpc under the bearers. 8 x 10 is only just under a m3 of concrete. wont take long to do.

stevec59 · 14 Apr 2010

Thanks Guys. I have asked the builder to quote for both, so I will see what the quotes come back like, obviously concrete will be more expensive, but might be worth spending a bit more on. The guy said that one reason for the concrete being more expensive is the amount of work involved; they need to dig out deeper, lay the cement, then come back, where as a dry mix they can do in a day.

Steve

stevec59 · 14 Apr 2010

For dpc I guess I can use ;-
http://www.toolstation.com/shop/Str...e+3m+x+4m+250mu+1000+gauge/d210/sd2787/p21675

21675 3m x 4m 250mu 1000 gauge
Or I guess the
54683 300mu 122 guage is better?

Thanks agian,

Steve

Thermo · 14 Apr 2010

they dont need to dig it out at all. a simple 4 x 2 bit of formwork. leaves the shed 4 inches above ground level but stops it sitting in the damp ground. we just use a roll of dpc not dpm, tacked to the bearers on teh underside of the shed

stevec59 · 15 Apr 2010

Thermo said:
they dont need to dig it out at all. a simple 4 x 2 bit of formwork. leaves the shed 4 inches above ground level but stops it sitting in the damp ground. we just use a roll of dpc not dpm, tacked to the bearers on teh underside of the shed

.

Yes,I did thanks about not digging out, but I guess you then have a 4" step into the shen, unless you build up the soil in front of the shed.
Can anyone comment on the toolstation dpm?

Thanks

steve

Deluks · 15 Apr 2010

stevec59 said:
Can anyone comment on the toolstation dpm?

Yes, as Thermo mentioned it's not what you need.
You need
http://www.toolstation.com/shop/Structural/Damp+Proofing/DPC+100mm+x+30m/d210/sd2787/p78151

attached between the bearers/floor joists of the shed and the concrete.

4" step is nothing, smaller than the stairs in your house. Put a 2" paving slab in front of the door as a step if you need to wheel something heavy in there.

No point putting polythene under the concrete base but opened up sand or cement bags strewn about will provide a basic barrier between earth and concrete, which might also help prevent it from drying out too quickly.

stevec59 · 16 Apr 2010

Thanks for that

I missunderstood!
As my beareres are small @ 34mm, I guess I go for the 112.5mm (27518).
This will allow mw to fold it up the sides of the bearers and staple it.

Steve

Deluks · 16 Apr 2010

Yep! Or you might want to get some 3x2 laid flat and use those as bearers, will strengthen the floor and raise it an extra few mm from the ground, plus will last quite a bit longer. (although tbh will probably outlast the shed!)

Another tip, whatever you decide to use as the base, make it slightly smaller than the shed itself, so that the shed overlaps it by about an inch, then lay a 6" wide channel of pea shingle around the shed, this will help prevent the base from getting splashed during heavy rain.

stevec59 · 19 Apr 2010

Deluks said:
Yep! Or you might want to get some 3x2 laid flat and use those as bearers, will strengthen the floor and raise it an extra few mm from the ground, plus will last quite a bit longer. (although tbh will probably outlast the shed!)

Another tip, whatever you decide to use as the base, make it slightly smaller than the shed itself, so that the shed overlaps it by about an inch, then lay a 6" wide channel of pea shingle around the shed, this will help prevent the base from getting splashed during heavy rain.

Thanks again Deluks. Been busy with the preservative at the weekend, very exhausting!!
I was thinking about putting some pea shingle around the shed, I thought about putting some of that black weed preventer down first, but I think this might stop the water going onto the ground? Any thoughts?

Also, I don’t have a stapler, would something like:-

http://www.argos.co.uk/static/Product/partNumber/7001507/Trail/searchtext>STAPLE.htm

'Includes 500 x 1.2x8mm staples, 500 x 12mm u-shaped staples and 500 x 10mm nails, all supplied in plastic carry cases.'

Do the trick, I did read some of the feedbacks, some one used it on his felt roof, I want to use it for the DPC

I guess :-

http://www.argos.co.uk/static/Product/partNumber/7016183.htm

Might been easier, but I don't want to spend another £48.

Steve

Deluks · 19 Apr 2010

Wouldn't even bother with that. the weight of the shed will hold it down, and you could use roof felt nails or small panel pins banged in halfway and bent over. Don't completely wrap the timber in dpc, it's more to stop dampness from leaching up from the wet floor, being timber they will still need airflow. So keep it loose.
The black weed stuff isn't a bad idea under the shingle to stop it from sinking into the earth. Could just as easily use polythene rubble sacks cut into wide strips. Don't worry about the water it will always find it's way down into the ground.

stevec59 · 19 Apr 2010

Thanks yet again Deluks, you have been a great help

Steve

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Shed Base?

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