New workshop .......yes, I have stopped dithering

[Benchwayze]

I wish I had the space. (Well I do really, but SWIMBO will NOT have a shed in the garden, and to her anything not made of brick, is a shed!)

There's a "ok to build a brick workshop" if ever I heard one :lol:

Well yes, but I am dithering,because if I do that, SWIMBO fancies 'shared-use' for storing garden tools and furniture etc!

Then the garage (my present shop) will become an extra downstairs room/WC, and I'll be no better off for space, and have a higher security risk! Plus, I don't want the hassle, and I suspect, neither does SWIMBO!

John

 

[Escudo]

Thanks for all the helpful comments and thoughts.

I am waiting for a quote on the concrete base option. I do not think this will be too prohibitive cost wise, although probably more than the slab route.

The supplier of the building is also going to provide a drawing for the groundworker with a view to using the concrete base as the floor of the workshop which to my mind is a good idea if possible.

I do not know how this will work in terms of using a brick plinth to sit the building on in accordance with best practice.

The front of the building cannot be altered and the level of the base must be the same throughout. How can this scenario fit in with the use of the brick plinth and enabling the concrete base to act as the floor of the building?

Here are a few pictures of the front of the building and the site;

The old retaining wall will be repaired with railway sleepers and extended to provide an area approx 25' x 20'.

On the concrete pumping side I found this type of service which may be just the job.

http://www.coppard.co.uk/pages/concrete-services/concreting-services.html

I will know a bit more next week.

I wish this was a bit easier. :roll: :roll:

Cheers, Tony.

 

[Escudo]

Hmmmm :? :roll: :roll:

There you go, fixed the post, you had a space at the end of the URL
DaveL

 

[woodsworth]

you will have a lovely view with all those windows. and a nice porch to sit at and enjoy it. I would imagine it would be hard for thieves to get up there as well.

 

[Benchwayze]

And those Norfolk skies as well... Yes, I am beginning to feel envy!

John

 

[Woody Alan]

The front of the building cannot be altered and the level of the base must be the same throughout. How can this scenario fit in with the use of the brick plinth and enabling the concrete base to act as the floor of the building?

A couple of choices Tony. The point of a brick plinth besides it's aesthetic quality is to raise the timber structure further away from the ground to prevent splash back from rain giving the bottom a good soaking leading to rot.
You could put a course or two on the whole concrete pad and raise the whole building by that amount. Or when the pad is laid make the whole pad sit much higher than surounding ground level. This could be acheived by shuttering to that height above normal ground level or dig away to a suitable depth around the pad and have lower level ground at that point. BT's smaller wooden exchanges http://www.geograph.org.uk/photo/1571511 are built on a raised concrete raft and the concrete is sloped away at an angle too. Thye also have quite a projection of roof and gutter so the falling rain is kept fairly well off the cladding and the sloping concrete means rain splashes away at an angle. There are thousands of these buildings across the UK and they have stood up for 60-70 years so far. There is a gap at the bottom of the cladding of an inch or two so it's not touching the concrete, there is a step in the concrete at this point.
Alan

 

[bignomis]

Hi just picked up on your topic and have some comments to make. Firstly I think the comment about the amount of wasted concrete in the pipe (you will also have to dispose of this as they won’t take it away) is very valid. I calculate for a 150mm pipe 60m long it’s about 1 cubic metre!!
I think also a concrete pump will be very expensive plus it will deliver it so quickly that unless you have got half a dozen experienced navvies you won’t be able to cope.
As others have commented I think you need to raise the slab above surrounding ground level and I think this is good advice. I think you need to make your slab so that the main frame of the building sits on the slab and the cladding just overhangs the slab. This way any water run off from the cladding will fall harmlessly to the ground rather than running horizontally beneath the frame sole plate.
I would suggest a thickening around the edge of the slab so the slab would stand 150mm above the ground, the edge thickness would be 300mm with the main centre area 100mm depth and some light reinforcing mesh. The concrete volume for this would be about 4.5 cubic metres which is about the same as a 150mm slab all over
You would of course need a bit of edge shuttering but this would apply to any concrete slab.
The area in the middle would need to have any organic soil removed and then built up to the required level perhaps using the sand from the ring beam although it would have to be compacted with a plate compactor.
The link to Coppard is a good one. This type of mixer will mix on site to your speed – a 6 cu metre readymix truck is no good because they will want to offload it in half an hour. A little 4wd skip loading dumper would be ideal or if the gradient is impossible a tracked one. As Coppard are in Sussex you should be able to find similar in your area.
Good Luck
Sketchup dwg attached hope it displays

 

[big soft moose]

your link is caught in the spam trap - clears after 3 posts

but that said it isnt displaying as an img anyway - fixed it for you, you'd missed the jpg tag off the end

 

[Escudo]

Thanks for further advice and for that drawing bignomis.

In the picture I see a raised area in the middle what is the purpose of this? The edges also seem to slope away.

Will raising the thickness of the base above ground level achieve the same advantages of the brick plinth on the basis that the cladding just overhangs the timber frame?

I would have thought that when pumping the concrete they would allow for material in the pipe and this would drop out at the end when they roll the pipe up?

Thanks for taking the time to contribute bignomis, and welcome to the forum.

Cheers,Tony.

 

[bignomis]

Hi Tony

In the picture I see a raised area in the middle what is the purpose of this? The edges also seem to slope away.

Basically the idea is instead of doing a 150mm thick slab all over is to concentrate the strength around the edges where the load is by a thickening (ring beam) and then the rest can be a reduced thickness – it’s roughly the same amount of concrete as 150mm all over but more where you need it and less where you don’t. The slope is just to avoid a weakness by having a vertical change in depth.

Will raising the thickness of the base above ground level achieve the same advantages of the brick plinth on the basis that the cladding just overhangs the timber frame?

Yes - just size the slab dimensions so that the structural frame rests on the edge of the slab and the cladding just overhangs. The brown band on my sketch indicates the part in the ground so the concrete edge stands up 150mm above ground keeping all your timber and cladding well clear of any water.

I would have thought that when pumping the concrete they would allow for material in the pipe and this would drop out at the end when they roll the pipe up?

It's a long time since I did any pumping. I seem to recall they blow a "pig" up the pipe to clear them. Best to take advice from a pump company if you decide to go this route.

Simon
[/quote]

 

[Jake]

If the shed has a timber floor (joists have been mentioned), does this really need a slab rather than strip foundations?

Or are you upgrading to a solid floor?

 

[Lons]

If the shed has a timber floor (joists have been mentioned), does this really need a slab rather than strip foundations?

Or are you upgrading to a solid floor?

IMO you should go for the slab for max strength especially when heavy machinery is involved.

I personally would put in a decent damp proof membrane (DPM) and then screed over the top to provide a finished floor which is solid, strong and quieter than timber would be.
If you so wished, you could incorporate polystyrene insulation below the slab for warmth (As per regs on home extensions)

"Quote: Basically the idea is instead of doing a 150mm thick slab all over is to concentrate the strength around the edges where the load is by a thickening (ring beam) and then the rest can be a reduced thickness – it’s roughly the same amount of concrete as 150mm all over but more where you need it and less where you don’t. The slope is just to avoid a weakness by having a vertical change in depth. "

This is exactly how you would create a raft foundation for a domestic works although it isn't deep enough for that around the perimeter and doesn't show the obligatory reinforcement / 100mm insulation (if polystyrene) / DPM and the consolidated hardcore base.

You're gonna invest a lot of hard earned and spend a lot of time in there. it needs to be solid, secure, warm, dry and ventilated. You'll kick yourself if you get it wrong. Anyway - your tools deserve the best!

ps.
I'm in the middle of a large extension which includes a room approx 4m x 4.5m internal.
Had intended it as a workshop - wife has just announced she wants it as a dining room so I'm really pissed off! - life's a bitch - can't afford a divorce! :x :evil:

 

[warrenr]

Tony

I assume the new structure is 20ft by 16ft and not 20m by 16m.

A six inch slab would need one load of concrete (6 cubic metres) and could moved to the site with three barrows by four or five people. An earlier string indicated a much larger quantity and pumping; hence my question about the size.

The main loading on the slab is likely to be differential movement of the foundation material and not the structure. You should excavate to create a clean foundation free of organic matter and soft patches (remove and refill with sand). Seal the foundation surface with a plastic sheet to avoid loosing cement slurry and think about hiring a concrete vibrator mounted on a screed board to get a dense high strength and durable concrete slab.

After poring the slab and once it starts to go off cover with sacking, blankets or similar and keep damp overnight to help curing and to minimise cracking.
Richard

 

[woodsworth]

If the shed has a timber floor (joists have been mentioned), does this really need a slab rather than strip foundations?

Usually a joist floor means that it is 3x2 joists if your lucky. I still think the floating slab i described would be best in this situation, Perhaps more then 8 inches deep at the sides though, to protect the wood from splashing and rising damp.

This means you'd have to make a hump so the slab is above grade and build a form around the outside or build up the wall around the outside something like this

so you end up with a slab looking like this

This is a detailed drawing of what the form work would look like.

If you want to have a better look i found the above on this forum

http://www.diychatroom.com/f19/concrete-footings-detached-garage-61300/index4/

All you would have to do is change the measurments to match your needs and where the porch is you'd just have to make the slab to match the top of the wall or nix it entirly and just put a few post forms and put a beam across to get the right height for the joists.

edit: wow i really like this idea as well in the same thread