# Build a shed Mike's way, without concrete



## MikeG.

There have been a number of enquiries lately from people who want to build a shed, but are worried about building a concrete base and laying a brick plinth. Whilst that remains the best way by far, I thought I would put together a thread for people who wanted a concrete-free alternative, without bricks. Please note that you should not attempt this technique for large buildings (say 20sq m or more), nor for buildings which need to show compliance with Building Regulations. If you plan on using a large lathe regularly I would also avoid a timber suspended floor, and would refer you tomy original thread on workshop building.

The principle of this alternative construction is to use readily available and cheap concrete lintels (from any Builders Merchant) to raise the timber the necessary 150mm above the ground. There is a minimum of digging, but topsoil must be removed around the perimeter, as well as all vegetation.

I show 2 alternatives, with the difference being the span of the floor. 

Here are the drawings:












Here is my typical corner detail for feather-edge boarding (this is a Plan Section):






Everything above the floor remains as per my original thread, and of course there are a myriad alternatives for the roof.

Now, I really should get on with some work!


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## MikeG.

I would just add that we get a number of people asking about buying a pre-made shed and erecting that on paving slabs and the like. Again, getting it up off the ground will prolong its life enormously, and I would urge those considering this way of procuring a shed to lay the concrete lintels as I describe above, and place their new shed on the top of that.


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## PAC1

I built my workshop/shed off three honeycombed dwarf walls. I dug and installed strip footing (the width of the shed) just in from each end of the shed and one central. then built three courses of honeycomb wall and fixed a wall plate on DPC above. I then ran the floor joists the length of the shed. I then laid 3/4 plywood floor and then built the shed off of the floor. 20 years later it is still good. The only downside is that the floor is about 15-18" above ground level so needs a ramp for machinery installation.


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## MikeG.

This alternative is aimed strictly at those who don't want to lay any concrete or bricks. There are a thousand and one ways of building a decent shed, but the options narrow considerably when you take bricks and a footing out of the equation. Too many people just plonk the timber on a paved area, then wonder why it rots in a handful of years. I have spent too long describing to people how to avoid this, so thought it time to actually do a drawing and show them how it's done.


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## PAC1

MikeG.":gn05m1yv said:


> This alternative is aimed strictly at those who don't want to lay any concrete or bricks. There are a thousand and one ways of building a decent shed, but the options narrow considerably when you take bricks and a footing out of the equation. Too many people just plonk the timber on a paved area, then wonder why it rots in a handful of years. I have spent too long describing to people how to avoid this, so thought it time to actually do a drawing and show them how it's done.


Mike I understood the aim. But your design requires a longer length of footings to be dug and more concrete. It is just that the concrete is precast rather than site cast. You also say crushed concrete in the footings. My method minimises the overall length of footings, concrete and brick by having 3 widths rather than 2 lengths and 2 widths. If you wanted to save bricks you could just have two courses of honeycomb wall.
Take a shed 16' by 8' your method has 48' of footing and precast concrete mine would only have 24' of cast concrete and then 96 bricks. Then there is rebar in your pre cast concrete. I doubt there is much between the two approaches in CO2 emissions.


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## ScaredyCat

Interesting, I wonder what your take is on what I made for a potting shed, it's held up so far but I'd be interested in opinions.

The cross pieces are pressure treated, under the fine gravel is broken brick chunks from the wall I found that the builders had left , when I dug out (it goes down about 10 inches. Shed sits on runners purpendicular to the cross pieces.


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## transatlantic

I did mine with the plastic shed base kits. The existing floor is a massive concrete slab. On that, I have the plastic grids filled with gravel. Then the bearers. Then the actual flooring.

So basically this, but it was a concrete slab, not grass.


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## MikeG.

PAC1":s6h52vmb said:


> ........Mike I understood the aim. But your design requires a longer length of footings to be dug and more concrete. It is just that the concrete is precast rather than site cast. You also say crushed concrete in the footings. My method minimises the overall length of footings, concrete and brick by having 3 widths rather than 2 lengths and 2 widths. If you wanted to save bricks you could just have two courses of honeycomb wall.
> Take a shed 16' by 8' your method has 48' of footing and precast concrete mine would only have 24' of cast concrete and then 96 bricks. Then there is rebar in your pre cast concrete. I doubt there is much between the two approaches in CO2 emissions.



I'm not suggesting doing it this way to reduce CO2 emissions. I am suggesting this technique so that people who don't have the skills to lay bricks, or the money to cast concrete, can have a better shed than just setting the thing on the ground. This isn't a contest. There are lots of ways of achieving the same thing. For good or ill, hundreds of people over the years have built sheds to my directions, and I have no doubt they'll continue to so do.........so the purpose of this thread is to provide them with an alternative to my preferred slab-and-plinth design. I have worked hard to keep the floor level low, to avoid the big steps you have, and also because of the height restrictions of Permitted Development outbuildings. As soon as you say "honeycombed dwarf wall on strip footings" (how do you keep vermin out of there?) you are missing the point of the thread.


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## MikeG.

ScaredyCat":1qrx2yj3 said:


> Interesting, I wonder what your take is on what I made for a potting shed, it's held up so far but I'd be interested in opinions.
> 
> The cross pieces are pressure treated, under the fine gravel is broken brick chunks from the wall I found that the builders had left , when I dug out (it goes down about 10 inches. Shed sits on runners purpendicular to the cross pieces. .....]



The principle I am trying to get across is to raise the lowest piece of the timber wall 150 above ground level. Your approach is better by a mile than sitting the shed on a patio or paving slabs, as so many do, but it doesn't achieve the raised sole plate which I consider a fundamental of a long lasting building.


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## MikeG.

transatlantic":3mg51lul said:


> I did mine with the plastic shed base kits. The existing floor is a massive concrete slab. On that, I have the plastic grids filled with gravel. Then the bearers. Then the actual flooring.
> 
> So basically this, but it was a concrete slab, not grass..........



Again, loads better than the typical, but it still leaves the bottom edge of the structure vulnerable to damp, and therefore rot. Depending on ground conditions and levels, it is possible that such a mat could fill with water if it is sitting on an impermeable base such as concrete.


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## transatlantic

MikeG.":1ux73i8y said:


> transatlantic":1ux73i8y said:
> 
> 
> 
> I did mine with the plastic shed base kits. The existing floor is a massive concrete slab. On that, I have the plastic grids filled with gravel. Then the bearers. Then the actual flooring.
> 
> So basically this, but it was a concrete slab, not grass..........
> 
> 
> 
> 
> Again, loads better than the typical, but it still leaves the bottom edge of the structure vulnerable to damp, and therefore rot. Depending on ground conditions and levels, it is possible that such a mat could fill with water if it is sitting on an impermeable base such as concrete.
Click to expand...


Yeah fair enough. I had considered that the concrete slab isn't going to be flat, and water could pool on top of it under the bearers, but I think it will be very unlikely to pool enough (45mm) to reach the bearers. I think if my garden ever flooded that bad I have bigger problems


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## MikeG.

The pooling water thing was only an aside. Falling water will bounce quite a long way even off shingle (pebbles), so to remain adequately dry timber should be well up above whatever the surface is, and able to drip dry. I'll bet if you look at your shed after rain you'll find the bottom couple of boards are damp even after the ones above have dried off.


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## transatlantic

MikeG.":3fd4717a said:


> The pooling water thing was only an aside. Falling water will bounce quite a long way even off shingle (pebbles), so to remain adequately dry timber should be well up above whatever the surface is, and able to drip dry. I'll bet if you look at your shed after rain you'll find the bottom couple of boards are damp even after the ones above have dried off.



Yeah - probably :-(


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## John Brown

Maybe you coud get the mods to add this to your original thread, as the instructions stand the risk of being lost in the noise here.


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## MikeG.

I've asked them to make this a sticky, so it should sit at the top of the sub-forum alongside my other one.


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## Duncan A

Thanks for taking the trouble to draw and post this, Mike.
I may have to replace a shed soon (yep, the bearers were placed directly onto paving slabs) and this will certainly be one way of keeping the job simple, it's a great idea.
Duncan


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## MikeG.

Duncan A":26go52ss said:


> Thanks for taking the trouble to draw and post this, Mike.
> I may have to replace a shed soon (yep, the bearers were placed directly onto paving slabs) and this will certainly be one way of keeping the job simple, it's a great idea.
> Duncan



No problem, Duncan. Feel free to ask about it at the time.

Those drawings took an hour or two, but will actually save me hours of typing in the long run, and I was clutching around at the time for anything that would stop me getting on with some work.


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## dom68

hi mike is it necessary to use prestressed lintels or is just reinforced ample? as in fence posts.. 

would it be possible for me to cast my own lintels in some kind of form using reinforcing rods? 

thanks..


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## dom68

also is it advisable to use treated timber for the frame?

ta.


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## MikeG.

Frankly I doubt it makes much difference. Timber framed buildings are treated as a uniformly distributed load, so as long as the lintel is correctly bearing on the substrate along its length it will only be in local compression. My hunch (unproven) is that you won't be able to cast your own as cheaply as you can buy them. I don't think you'll find a fence post which is 150 in one dimension. The ones I am familiar with are about 100mm square, and although that is better than sitting the shed on the ground, it isn't really high enough.

Treated timber? Absolutely. Don't even think of not doing so.


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## dom68

ok mike thanks very much. im planning on building an 8x6 just for storage then if all goes well move on to a workshop.. poss 18x12ish.. thanks for all the info you post on here!


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## dom68

i actually have a old mate (not seen him for a long time!) who has a fencing business.. i used to work for him long time ago.. i was thinking i could ask him to provide the concrete if i provide the form..

would it make a difference if two lintels are used length ways to make up full length of shed? 

cheers, dom.


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## MikeG.

:lol: I hope they're feet rather than metres!!


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## MikeG.

dom68":22hlab7e said:


> .......would it make a difference if two lintels are used length ways to make up full length of shed?
> 
> cheers, dom.



No, absolutely not a problem. I should have made that clear. Just keep the gaps tight (and at the corners) otherwise you'll have mice or wasps nesting in the void.


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## dom68

haha.. yes feet.. not sure id fit an 18 metre shed in the garden ;-)

ok thats bril.. thanks again

dom.


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## HOJ

We use 150mm X 100mm concrete lintels, as part of our construction method, we generally keep the lintels to a max length of 1200mm long, found that longer than that length they have a risk of having a camber in them, plus, we can handle them easier.


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## Sideways

I've learnt a great deal from these threads Mike, thanks for sharing the ideas behind them as well as the designs themselves.
I plan to adapt your design to build a small (1.8 x 1.2M) uninsulated storage shed raised up on concrete lintels as you recommend.
I propose to move the 9mm OSB3 skin to the outsideof the framing as I don't need either the insulation or the smooth inner walls, but do like the stiffness that it will add to the frame.
Having the framing open on the inside will aid air circulation and make it easier to see any problems as the years go by.

I'll then use 25mm battens to support the cladding off the OSB to reduce the transfer of damp from rain soaking into the cladding.
*In this construction, is there any significant benefit from fixing a membrane to the outer surface of the OSB before fixing the battens ? *
The shed is in a sheltered corner of the garden so driven rain should not be an issue. 
Thanks.


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## MikeG.

For a store shed only (ie without human activity happening inside), what you are proposing is spot on. It is in fact exactly what I did for a shed I built (last year I think). No, you don't need a membrane over the OSB so long as you have counterbattens forming a 25mm airspace behind the cladding. For that sized building, ex 50x50 timber is plenty for the framing, with ex 100x50 for the lintel over the door.


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## Sideways

Perfect 
Thanks Mike !


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## dom68

hi mike.. i seem to be only able to find 140x100 lintels. if i wanted to use 4x4 for the sole plate would this be acceptable? im thinking of the gap between the ground and the underside of the floor..

also is there any reason i shouldnt use concrete screws for fixing the sole plate to the lintel rather than the galvanised straps? 

thanks dom.


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## MikeG.

Yeah, I should correct my drawing. 150 is the nominal size, including a mortar course, so the actual lintel is 140 x 100. That's fine. The reason for using straps is so as not to pierce the DPC. Buy a cheap roll of the universal galvanised MS strapping, and cut off the lengths you need. Screw and plug into the inside face of the lintels.


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## dom68

ok thats great.. thanks mike.


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## flying haggis

when I built my shed I wrapped the bottom edge of the bearer with 3" wide dampcourse plastic so that the wood didnt touch the concrete with the only fixings being at the ends on top


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## MikeG.

There's an in depth thread here documenting a workshop build using this technique. Well worth a read for anyone considering building a workshop this way.


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## DBT85

Mike,

I'd be interested in your opinion of the work being done by Ali Dymock on youtube and his website, trying to clarify details for people while he does his own "garden room".

His videos are quite informative for those of us not au fait with all of the details.

I'd especially like your opinion on how he's raised his floor up on block piers.

https://www.youtube.com/channel/UC4UDFz ... qTA/videos


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## matkinitice

This is a good question.

Can you answer this Mike regarding the use of the block piers in the previous videos? I happened to watch some of these videos recently too so would ask the same thing myself.

Clip here is only a few mins long: youtu.be/Hyfbb2FRkV8?t=477

Much appreciated.


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## MikeG.

I'm only commenting on the floor and sub-structure.

Structurally fine. The massive downsides are two-fold. Firstly, there is a huge step up from ground level, and this has major implications for those trying to build below the Permitted Development heights, as well as for getting machinery into the building....never minding mobility issues and the practicality of climbing 3 steps (there will need to be a landing, so the steps will take quite some room, too). Secondly, creating an open void inaccessible to humans is a recipe for vermin to move in. If you provide a habitat for rats you will get rats. Badgers and foxes would also be interested in such a sheltered spot, safe from humans. Even bumble bees or wasps moving in under there could make the workshop unusable in some summer months.

The reason I went to the trouble to provide my design (in the OP) was to help people avoid those two major issues. My view is that building on piers is to be avoided at all costs.


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## matkinitice

Excellent, thanks for the comments.

I'm a house move away from building my workshop but good to know the options. This and the other thread has been very useful. I'll be sure to share my progress when the time comes.


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## DBT85

A late reply from me but thanks Mike! Are you not commenting on anything else because you were not asked or because your mother said if you have nothing nice to say then say nothing? :lol: 

Still so many things to think about before I actually get to the point of building.

I assume that with the lintel design the void created under the floor doesn't become a vermin haven simply because there is no easy way in? 

Moved the other questions to the other thread as I'd need a slab for my size.


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## MikeG.

DBT85":qouvdt6g said:


> ......I assume that with the lintel design the void created under the floor doesn't become a vermin haven simply because there is no easy way in? ........



Correct.


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