Shed rebuild project questions

Hi Noobie here with some questions.

I have an existing timber shed at the bottom of the garden and am thinking about knocking it down and rebuilding it, so I have a few questions.

Starting point
There is a concrete base/plinth already in situ with an extended wooden part making up the other half of the current shed. What I'm thinking of doing is replace the whole structure with a brickwork structure measuring an overall external size of 355 x 286cm. See attached.

1. Can I get away with using a Thermalite 'shield' block 440x215x140mm to build up and the walls from?

Part of the build will be set on the concrete plinth already there and the other half set of a concrete foundation which I would put in.

2. Will the Thermalite 'shield' blocks be sufficient to repel moisture? Or
3. Should I use another grade of thermalite block?
4. How deep should I go for the sunken half, one block or two?

I would put in a dcm on top of the first course and use thin joint masonry joints to help cut out the moisture. The overall height will be nine blocks high (193.5cm) with a light timber roof which will be covered with Permaroof on top.

Two sides of the build will be about 20cm away from a timber fence (back) and a neighbors brick outhouse (right hand side). There will be a door and probably one wooden framed window going on the other sides, these two sides will be cladded with wood for asthetic purposes. There is an electric supply going in for lighting.

5. Is there any thing else I should be asking/thinking about?

Thanks

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You probably require planning permission for an entirely brick built structure, not so if it's a timber shed. You'd get away with a hybrid: timber frame on a dwarf brick or block base.

It makes no sense to mix the floor structure. You could get differing rates of settlement meaning your wall structure and floor may start to crack. You should just lay an additional concrete base tied into the old one. making sure you have a well compacted base of decent depth.
Relatively simple stuff.

If you want an insulated floor, you could just put down damp proof membrane over the whole (concrete) floor, going up and under the dpc. 2x2 battens with insulation in between, with sheets of ply or t&g osb put down over this. (Depends on usage though, not very useful if you want to bolt down a pillar drill)

you shouldnt need planning permission as long as ur floor space is less than 15 metre2

and it doesnt matter whether u make it out of wood brick or mud lol as long as its 1 metre away from any boundary.

If it isnt 1 metre away and is bigger then 15 metre squared then it has to be out of brick or block and not wood and I quote

"Building a detached garage of less than 30 square metres floor area would not normally need building regulations approval if:

1: the floor area of the detached garage is less than 15 square metres.
2: the floor area of the garage is between 15 square metres and 30 square metres, provided the garage is at least one metre from any boundary, or it is constructed from substantially non-combustible materials"

Im assuming non combustible materials is brick and block so that they cant ignite and burn.


So no planning permission required, then link for my quote is here a long with a lot more information


http://www.planningportal.gov.uk/england/genpub/en/1115315233162.html
good luck

Thanks Guys.

The shed is only going to 9.8m/sq so no planning needed, it's not going to be a gararge (no access whatsoever) just a shed containing all my crap, paint, garden stuff etc. All it needs to be really is watertight and protected from the elements, had a few things ruined in the one I have and the roof continually needs repair/replacing.

If it's brick I can shelve it wall to wall which will make things a lot easier.

The questions still need answering are;
1. Will the Thermalite blocks I've suggested be sufficient (see pdf below) 244x215x140mm Sheild? and 2. How deep should I go for the foundations, 1 block or 2?

http://www.edisonandcrapper.co.uk/Misc/Pages-from-Thermalite.pdf

RE point 2. Other than the shelving there will no excessive weight i.e. roof as this will be a light wooden shed affair, so only the wall weight to consider. This will be a lot cheaper than putting in another concrete plinth to build on will it not?

Another question or three; Could I use a thinner block i.e. 100mm thick instead of 140mm?
If so which of the thermalites should I use i.e. Sheild or Hi-Strength7?
Could I even use Turbo (100 or 140mm) or would that compromise the moisture absorption?

Thanks in advance

Builders, Friday night, pub! sounds familiar, anyway as I was down the pub on Friday and I had plenty of recommendations, not all helpful but one thing that did come up was what deluks said earlier, why not lay another foundation to match the existing?

Well, as money is of short supply, especially for a shed my question is, what are we talking about, money terms, for a new plinth/solid foundation? (see original diagram for size). Nobody could tell me a price, funny that.

Anyway open to suggestions, thats why I'm here. Plus if you would like to read above/below what suggestions to the brick/block choice? Didn't get much joy there either.

I might be able to get the bricks/blocks quite cheap, 100mm, although they would be commercial i.e. the solid breeze type and heavy, if you know what I mean, but still don't want to spend a fortune, am saving for a blu-ray. DOH!

Without doing the sums cos I'm off to bed.... Concrete base will need:

some old rubble and hardcore £free

Bag or 2 of ballast £30 - £45 a bag, depending where you shop.

A few bags of cement at between £2 - £3 each.

1 shovel

1 hosepipe (connected)

2 strong arms


For foundation blocks, stick with concrete for the first few courses, cheap and quick. Thermalites after that, cheap and quick and light. 100mm will be adequate.


Get the roof right once and you won't be forever fixing it!

Have since spoken to a builder regarding what blocks to use, although brief, he suggested celcon hi-seven blocks.

Are celcon cheaper than thermalite?

I was initially going with 140mm but now want to go with 100mm blocks taking into account the size of build and height are hi-seven or 7n blocks okay?

I was wasn't planning on pillars just single skin all the way round bar a door way/frame is this okay?

The roof will be lightweight ie angled flat roof.

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