Another question about shed bases.

[BigRobCanUFixIt]

Hello all.

I am looking at making a base big enough to get 3 sheds onto.

The size I will need is 4mx8m

I am looking to do this as cheap as possible, but also in a way that will stand the test of time.

My first thought was hardcore capped with 6 inches of concrete. But the concrete alone was coming in at £500 thats delivered premix. Im not sure if mixing 4.8m3 is going to be achievable in a long weekend in a mixer in the garden and whethet the 14ish tonnes of material will be much cheaper than the premix.

So I am now thinking about laying slabs onto hadcore with either sand or dry mix on top at a thinner proportion to the concrete. Would that size area be do-able cheaper than the concrete option. Thats sand or drymix and cheap and cheeful slabs. for 32m2 would they be cheaper than 500 quid.

Thanks in advance.

Rob

 

[Richard C]

I'm sort of amazed by the lengths some want to go to for a simple shed; it’s not an extension or a cons, it’s just a shed &, if it’s timber, comparatively doesn’t really weigh much. I’ve only ever used 6ft reinforced concrete fence barge boards laid on a 2 inch compacted sharp sand base. My current shed is about 10 x 4m, a sort of shed + enclosed barn thing & was erected around 5 years ago. A slightly smaller one I built at my previous property has now been there 23 years & one before that & my mother–in-laws greenhouse even longer than that; never had any problems with any of them.

 

[big-all]

18"x18" quality slab set on concrete brick in the centre topped with felt/dpm arranged in a 2ft square pattern with the 3x2" floor timbers
this gives a cheap strong way off supporting sheds with no risk off water using the base to run under and cause problems

my 12x10ft shed

http://s21.photobucket.com/albums/b270/bigall2005/?action=view&current=e1e47346.pbw

 

[Richard C]

More of a workshop than a shed & very nice it looks too . With all my timber sheds I cover the bottom with roofing felt, it keeps them nice & dry inside & helps prevent premature deterioration of the timber floor.

I’m doing another 6 x 3m one later this year for garden equipment storage & a part open annex for log storage. I’m also building a large garage/workshop but that will be brick construction under a pitch tile roof & that will have a decent concrete base with a DPM.

 

[RedHerring]

A comment on your mixing that quantity on-site.
I've found that mixing 1 cubic meter is a long days work. That was for me & 1 other doing the wrap-around patio in sections, approx 1 cubic meter per day every other day, for 6 sections.
It's not so much the graft but the time taken to mix each load.
That was one person mixing & shifting and the other leveling & tamping.

 

[RedHerring]

I’m also building a large garage/workshop but that will be brick construction under a pitch tile roof & that will have a decent concrete base with a DPM.

Richard, just a comment on my experience this winter. Despite having 100mm polystyrene insulation in the floor (& DPM). I find I'm getting condensation on the floor when I'm using gas portable heater and a de-humidifier. Not a lot, but a bit. Humidity is in the 85% - 90% range mind. (Single skin 100mm block and not finished rendering all the walls yet.)
I get condensation on the rollershutter door also but I expected that. It's only a problem when the bottom seal freezes and the motor ain't strong enough to break the frozen seal.

 

[Richard C]

I find I'm getting condensation on the floor when I'm using gas portable heater and a de-humidifier. Not a lot, but a bit. Humidity is in the 85% - 90% range mind. (Single skin 100mm block and not finished rendering all the walls yet.)

The gas heater could be the cause of your condensation problem. I’ve yet to decide on the detail spec. for my workshop but I’ll bear that in mind, thanks.

I have another attached, single garage which is used to store an immaculately restored classic car (all my own work ). I don’t use it as a workshop & is the reason why I’m building a separate one. The garage is not heated but very well ventilated & the car has lived in there under a breathable cotton cover for 5 ½ years now with no sign of condensation or any real deterioration in its condition.

 

[BigRobCanUFixIt]

Ok thanks for the advice so far.

I think I will go for the piers and timber solution. As mixing concrete is going to be a mission. I like the concrete fence post suggestion too.

I'll probably make a concrete path along the front of the sheds so that I dont get too muddy as the end of the garden can tend to be a little bit soggy in the wet, Although I think by time I have knocked down and filled in a pond about 10mx3m and 1.5m deep that will give the soggy lawn somewhere to drain to.

And I think the space behind the sheds I will just use some shingle or gavel to make an area to dump stuff out of sight.

Should I consider filling the void under the sheds with anything? Like gravel or dirt. To keep out the wildlife etc.

Rob

 

[big-all]

space underneath is great for storing clothes airers clothes poles treated timber and many other long thin things

 

[Richard C]

I like the concrete fence post suggestion too.

That’s reinforced gravel boards - 300-350mm wide not the posts.