Cheap and Easy Shed Base?

pmartin86

Morning All

I've been lucky enough to have been given a shed that I wasn't expecting, very similar to this one:

Forest 7x5 Overlap Dip Treated Apex Wooden Shed | Shedstore

It's about 5 years old and in reasonable shape, so I see no reason I wont get a few good years out of it.

My issue is that I moved house about 9 months ago, and other than attacking the rampant weeds and hosing down what's there, I've not touched the garden at all, and plan to majorly landscape over the coming years, so the spot where i WANT to put the shed, is currently a rotten set of flowerbeds/decking. I've got a suitable spot that it can sit for a few years (its life?) thats good thick, fairly flat concrete, but it has an area in one corner that gets ponding water, about half an inch to and inch deep - Obviously I can shim the base to level the shed, but what can I do to protect the wood from rotting here? I've fairly limited time and budget  and I would love to build a proper base, but this wont be happening.

I was hoping it might be as simple as knocking up a quick frame of 2x2s, levelling it with the ground ive got and painting the frame with some leftover roofing bitumen I've got, then siting the shed on top of this? Obviously it won't last forever, but if it keeps the main shed alive along enough for me to get the rest of the work done, it will do the job, any thoughts? 

stuart45

You could lay some bricks as the bearers. Easy to level and won't rot.

pmartin86

Check you out with your simple logic and stuff! Proves that overthinking things is often a bad idea! 

I've got a lovely stack of breeze blocks doing nowt from a (very) dodgy raised bath the previous owners left here (literally a "floor" of breeze blocks under a bit of plyboard with the bath on top and some half-&$%ed trim around the sides), so they will do the job! What sort of spacing would you recommend? I assume the weight of the shed will be enough and I wont need to bed them in with mortar?

Gunner276

A bed of mortar would help you get them level though!

stuart45

I'd bed them in mortar to get them dead level. If the shed has a level base it is better for the shed as the walls and roof are less.likely to distort and fall apart. 
For a base of 7x5 lay the blocks flat. A course at each end, and 2 inbetween evenly spaced. A cheap roll of DPC on top of each course of blocks.
You need 12 blocks and 4 cuts. 3 and a cut will do 5ft.

Bendy_House

If your shed is near exactly like the one in the pic, then it'll have these 5 'joists' running, evenly spaced, from front to back?

That's 4 'spacings', each around 375mm wide. A breeze block is 400mm long(?), so one will catch two joists. And then you'll need a few blocks up t'middle to support the central joist.

So, I think I'd lay the blocks so they each catch two joists, so that means width-wise - make sense? Ie, the shed is a rectangle, so are the blocks, but the blocks will be a right-angles to the shed direction. (When you look at the side of the shed, you'll see the block 'ends', 200mm wide x 100mm high, yes?)

One block near the back (an inch or so in from the end of the joist), one near the front (ditto), so another two in between will give around 400mm 'unsupported' spacings in between each block - I think that should be perfectly fine.

Ditto on the other side - catch 2 joists with each block.

Then a long-ways run of blocks down the middle for the central joist - I guess you'd only need three blocks here? 11 blocks or so in total?

Lay out the blocks so that the outside edges of the shed joists land neatly level with the block - you don't want any block sticking out beyond this. Ok, a quarter-inch...

Then check the blocks for level. I doubt they will be... The ideal solution is to mix up a stiff batch of 'weakish' mortar - 6:1 at most - and place each 'low' (or all...) blocks on these. Use a straight edge and a level and tamp them down until all are level. Leave to set.

A layer of DPC between the block top and joists. And then soak the joists in Everbuild Lumberjack, espec where the blocks are.

IF this location is where you'll have a shed anyway, then this is worth doing. Once you raise the shed off the ground, it'll last 'forever'.

You will also likely find that the shed you are getting is very rescuable, and a good spray of Lumberjack, especially along the bottom boards, around windows and doors, and corner posts (SOAK all these!) followed by 'garden shades' will completely transform the shed, and make it survive. You'll have saved yourself a good £ew £undred.

If it's temporary, then just lay the blocks straight on to the slab, start with the highest block and take levels across to the others. Pack out on top with timber offcuts - pretty much anything you can find - to get them levellish.

stuart45

One thing when starting to lay the blocks is lay the first block at the highest point. You can always bump up the mortar joints to get the others level, but if you start at a low spot you won't get the blocks down to the correct level.

pmartin86

Thanks for your comments all, given me enough to go on I think!

It's what I like to call a temporary-permeant placement, It's not where the final plan is for the garden, but its the only suitable spot at the moment., however I'm probably 2-3 years away from any serious efforts in the garden (lots to do indoors first) and the hardstanding I'm looking to use now will eventually become a spot for a greenhouse if I get my way, so id rather avoid "ruining" it with a permanent fix. 

As for the shed, yes, it's in pretty decent shape, very little damage (other than the unpleasant colour its been painted!) but I've got some garden shades left over from the last house that I intend to use. I'll take a look at ever build lumberjack, so thanks for that - That being said, how long SHOULD a wooden shed last? I've always ended up with brick sheds or garages so never really needed to worry - its probably not something I would buy myself, but gift horse and mouth and all that. If I can get 5 years out of it, great, if I can get 20, I'm not going to complain!

Edit: As a quick aside, some the felt is looking a bit rough, will a roll of this do? I assume this will need replacing every couple of years?

Roof Pro Green Shed Felt 10 x 1m | Roofing Felt | Screwfix.com

Bendy_House

If the slab isn't level, then it'll need levelling in any case if the shed isn't going to distort, but this can be done non permanently by just placing the blocks, checking the levels on top, and adding packing pieces on top of this to suit. 

If you visit a local pvc window fitter, they'll have a skip full of pvc fascia offcuts around 8 or 10 mm thick, and these will be ideal - and they'll thank you for taking it! This can be scored with a craft knife and snapped to make pieces for the joists to sit on. A dab of Stixall will bind them together and prevent them moving as you life the shed on. When you move the shed, it'll all lift away with no trace. 8/10mm variation will be fine for a shed that size, so you won't have to go more precise than a 'layer'.

How long will a shed last? 'Forever'. If you stop damp from the ground going into the joists, treat it all with Lumberjack, and give it a protective coat, it simply should not rot - ever. The secret is to protect the joints and parts where rain would go, and to make sure these are soaked in preserver. Then liberally coated with a top coat. I mentioned the outside corner posts, window and door frames, fascias, the bottom boards in particular, UNDER the bottom boards, anywhere rain will settle or get in to - focus on these.

That felt is 'fine' and will serve for 5 years or so. There are alternatives, but not worth it if 5 years is all you want. I'd try and bond the felt in place (Stixall, or a roofing adhesive) rather than use nails. Watch out for the felt cracking where you take it round the eaves. 

pmartin86

Thanks both - I think I'm just going to bit the bullet and do a "proper" job. I'll get some mortar and some lumberjack, use the breezeblocks I've kept "just in case" and spend the weekend sorting it. I expect my 2-3 year plan will probably be 4-5 (bloody renovation work next goes to plan does it? ) so might as well put the effort in, bonus points if I can re-site it in that time into its "proper" spot, which I suppose will depend on my efforts now.

I assume a more "permanent" roof would be better overall? EDPM or the likes? If so, ill probably just stick the cheap and easy on for now and look to do that next year.

FreeBear

If you use a weak mortar mix (say 10 parts sand, one part cement), when you need to move the shed, the blocks & mortar will come away real easy.