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



## Escudo (24 Feb 2010)

One or two of you may remember that for a year or two I have been dithering over organising a new workshop. 

Plagued by issues over where to put it, whether to self-build or buy an instant solution, or even whether to move house for a place with some outbuildings, etc etc. 

Well, I have finally cracked and ordered a new workshop, home office type building.

I just don't have the time to build the workshop myself and had to stop kidding myself otherwise, and in the cold analysis there was only ever one place to put it in our terraced garden.

Moving house was not really an option as the stamp duty alone would have amounted to more than the cost of the new workshop, base and one or two new machines I have in mind.  

Here is a sneak preview of the building which will be arriving at the end of March, 20 x 16 (inc. the veranda, where I plan to put my hammock).  







I now have to organise a base for the building which is at the top of the garden. My mate Dick, who runs a groundworks and civils firm is going to do the work on the base and some other work on a retained wall behind the new workshop.

I asked him to prepare for a concrete base in accordance with Mike's excellent specification. This however, will be very expensive as the concrete will have to be pumped up to the site. An alternative option he suggested is a base constructed from heavy concrete slabs, which is much easier and a cheaper option. 

I am not sure if this is a good idea or not, and would value the forums opinion? 

I don't want to "spoil the ship for a h'aporth of tar" as they say. Will this type of base be strong and stable enough? What method of construction should I request, specification?

Whilst searching for information I stumbled on this site;

http://www.ecobase.biz/index.html

Seems a bit wacky to me - but could this be another solution?

Look forward to receiving comments, guidance before I decide on the base.

Cheers, Tony.


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## wizer (25 Feb 2010)

Well that's next years bash sorted out! 

Well done Tony. I'm envious. Very envious.


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## warrenr (25 Feb 2010)

Hi Tony,

My first contribution; but in an aspect in which I am qualified as a civil engineer. 

Much depends on the state of the ground and whether you going to house heavy woodworking equipment.

A good sound base will be needed if you are going to house heavy equipment. A concrete slab on a good foundation (sand or silt) would be ideal with some gash steel reinforcing to limit any cracking if you can lay your hands on some. Clay may give some problems but probably only localised minor cracking if you put in a drainage layer (say 6") under the concrete slab. 

Heavy duty paving slabs (old 2" municipal slabs) laid on a mortar layer would be second option on good ground which has been well compacted. Again an additional 6" hoggin or drainage layer would be sensible on clay.

I am not familiar with the eco base solution; but I would think it would tend to punch into the ground if there is heavy loading and this would cause some movement and could put the workshop structure under stress. The loadings that they quote are likely to be only for the material used and may not reflect the overall loading capacity. Plastic will degrade in sunlight; you need to ask about the expected life of the material and whether it should be covered (at edges)

I hope this helps :!: 
Cheers Richard


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## Mr Ed (25 Feb 2010)

If I was spending some money on a workshop, personally I would do a proper job and cast a concrete base. Although it will cost a bit more, you know from that point onwards that it will do its job.

An alternative, which I favour for decks, is concrete blocks set on concrete - a bit more robust than slabs, but only suitable if the building bears down as point loads;






My advice though, is go for a cast concrete base.

Ed


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## Woody Alan (25 Feb 2010)

Hi Tony,

Glad you are finally getting sorted. Firstly forget the green thing in no way is it suitable for what you want. I would go with the reinforced slab with thickened edges, that is what I used on my "summerhouse" and that is smaller than your proposal. As for the slabs I don't like the idea. They are hard to get level and have the potential to shift unless they are layed on concrete which defeats the object.
My suggestion if possible is to get your "all in" up to the area where you are going to concrete. This could be by barrow or even get one tonne bags craned over to the top and then do your mix on site, this avoids moving wet concrete and the commitment to acheive in one session.
An alternate might be a precast beam floor.
http://www.milbank-floors.co.uk/bb_tech.shtml 
The only thing with that is you'll ned to put in a decent footing and you are back to a considerable amount of concrete. A dilemma indeed.

Alan


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## matt (25 Feb 2010)

How much is the premium to pump the concrete? If it were a small shed base I can understand your reticence, but as a percentage of the total project cost in this case is it really that significant?

Out of interest... In a terraced site are there implications when it comes to plonking a heavy lump of concrete on top of a terrace? Are there structural considertaions to stop the thing wanting to make its way downhill?


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## devonwoody (25 Feb 2010)

Hope all goes well with the new workshop, the demo looks good.


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## woodbloke (25 Feb 2010)

Tony - looks like the new 'shop is going to be fandabby :lol: Whatever base you opt for (personally I'd go for the concrete raft) make sure it's strong enough to support the weight of all that Felder equipment :wink: you're going to stuff it with.
I know that you're also thinking about a new bench, but what about any new Slope inducing hand tools to go in it as well? - Rob


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## Escudo (25 Feb 2010)

Thanks for all the comments and advice.

I agree with the view that a concrete, reinforced slab is the best type of base, it is also the most expensive option and even more so in my tricky situation, given the location for the base.

Here are some pictures of the garden from a previous thread;

https://www.ukworkshop.co.uk/forums...-t33115.html?highlight=moving heavy equipment

The ground is very sandy and apparently this is an advantage.

The plan at the moment is to level up the site, complete work on the retaining walls behind, and take stock. 

The slab option has been explained to me as follows;

Compact the ground, and if need be add a hardcore layer before also compacting this down.

Bed some 2" heavy slabs on 50mm of strong dry cement mix extra strength at the edges.

The floor of the office building is made from pressure treated timbers 45mm x 75mm. The joist are approximately 140mm apart and the batons are 375mm apart? I am just checking this last piece of information, which doesn't seem quite right if my understanding of these terms is right. :? 

I am also going to get an idea of the cost of the concrete slab approach to see how much more this will be.

The more I can save on the base, the more I will have for all that Felder gear Rob. :shock: :shock: Alan, I may just need you to lend me some money the way this is looking :wink: 

Thanks again for advice and thoughts, much appreciated.

Cheers, Tony


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## Woody Alan (25 Feb 2010)

> Alan, I may just need you to lend me some money the way this is looking


Tony, my boy! you know me, my rates are always very reasonable. Just come and see me and my mate Dodger and we'll work summut out!
On the plus side Tony you'll be able to let that out as a holiday let if needs be...might even take you up on it myself....if you don't tell the missus 

Alan


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## Woody Alan (25 Feb 2010)

> The joist are approximately 140mm apart and the batons are 375mm apart? I am just checking this last piece of information, which doesn't seem quite right if my understanding of these terms is right.


Also just re-read that bit...sounds wrong to me too! joists at 375 15-16" sounds fine but the 140 or 5 1/2 " or thereabouts ?? not sure what that would relate to.

Alan


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## Lons (25 Feb 2010)

warrenr":1qf3eyoo said:


> Hi Tony,
> 
> My first contribution; but in an aspect in which I am qualified as a civil engineer.
> 
> ...



+1

All depends on existing ground stability but as an experienced builder I would always recommend the best base you can get.
False economy to scrimp and find the (expensive) workshop has moved and leaked all over your precious machinery.
Weight of machinery is an important consideration also.
If you go for a conc. slab, specify it's use to the supplier who will formulate the correct mix for the job and I suggest you get proper reinforcement mesh from a builders merchant. 2 thicknesses available and sheet size around 3m x 2m (thinnest 6mm from memory is around £17 sheet = vat).

PS
Jammy pipper......how did you get the other half to agree? - Can you have a word with my missus please.


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## warrenr (26 Feb 2010)

Tony,

With a sand foundation and machinery loading, I would go for a 150mm thick slab with the mesh reinforcement as suggested. 

If the sand is clean and compacted, this should not move and the mesh will help with crack control. Belt and braces would be to use a thicker slab.

Richard


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## Dibs-h (26 Feb 2010)

matt":120cfpsa said:


> How much is the premium to pump the concrete? If it were a small shed base I can understand your reticence, but as a percentage of the total project cost in this case is it really that significant?
> ?



If you get the trucks with a boom arm - it can be around £750-£1k per visit. Or there are the smaller (usually independent operators) who use 6-8" pipes that clamp together and charge £250 per visit.

I've used the latter twice - once for the ground beams and then for the raft - worth every penny, as it was all in and they were done in < 1hr each time.


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## BigMac (26 Feb 2010)

Dibs-h":3lzyuyy2 said:


> If you get the trucks with a boom arm - it can be around £750-£1k per visit. Or there are the smaller (usually independent operators) who use 6-8" pipes that clamp together and charge £250 per visit.
> 
> I've used the latter twice - once for the ground beams and then for the raft - worth every penny, as it was all in and they were done in < 1hr each time.



Does that work 60m up a steep, non-straight slope?

I think thats the OP's problem.

Would a mini dumper manage the climb? http://www.tcp.eu.com/sales/tracked/mini-dumper.html

Either to take up aggregates and mix on site or just to ferry pre-mixed up at a reasonable speed.


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## Dibs-h (26 Feb 2010)

BigMac":2n9xp09u said:


> Dibs-h":2n9xp09u said:
> 
> 
> > If you get the trucks with a boom arm - it can be around £750-£1k per visit. Or there are the smaller (usually independent operators) who use 6-8" pipes that clamp together and charge £250 per visit.
> ...



When they did mine - they were pumping a distance of something in the region of 30m, so don't see why they couldn't pump 60m, after all it's only more lengths of pipe that are needed. The pumps are piston pumps, so don't see 60m uphill being an issue.

The pipes were bending round cars, gates, down steps and round, so straight it doesn't need to be.


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## woodsworth (27 Feb 2010)

I would go for a 6 inch slab with the perimeter being 8 inches at least to a distance of 1 foot into the building. I would also reinforce it with either a mesh or a grid of rebar on 16 inch centers. Basically you are building a floating slab. If you have to pay for a pump and someone to do the ground work you do not want to scrimp on your slab. Rebar is like insurance in my mind, not completely necessary but it will lessen the likely hood of it cracking.


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## Benchwayze (27 Feb 2010)

Hi Tony.

I had my front drive block- paved about ten years ago. 
It was excavated to a depth of about three feet (A metre or so I believe) and the builder had a great lorry-load of genuine road stone rollered in. 

The blocks are solid as a rock, as flat as the day they were laid, and regularly withstand my son's recovery vehicle when he pops in for lunch! 

I'm not recommending paving blocks (Unless you fancy them) but I am recommending having a proper base, with well tamped road stone under the concrete. 

As for the workshop, you are well qualified to assess the quality of a wooden building. It looks fine to me, and if it is cedar wood, then with average care, it will last as long as you'll need it. 

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!)

Good Luck 
John


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## Shultzy (27 Feb 2010)

Benchwayze":2vegh191 said:


> 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:


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## Mr Ed (27 Feb 2010)

Dibs-h":rwi6gpih said:


> BigMac":rwi6gpih said:
> 
> 
> > Dibs-h":rwi6gpih said:
> ...



Provided you get the right plant, you can pump that - I have pumped concrete to the top of a 16 storey building before now without issue, but it is a substantial piece of kit. The bigger issue will be that the pipes will still be full of concrete and needing to be emptied into the pour at the end, so with a small base and a long pump run half of the concrete you need will be sat in the pipes between the foundation and the pump.

Ed


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## Benchwayze (27 Feb 2010)

Shultzy":xzkokq54 said:


> Benchwayze":xzkokq54 said:
> 
> 
> > 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!)
> ...



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


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## Escudo (27 Feb 2010)

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.


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## Escudo (27 Feb 2010)

Hmmmm :? :roll: :roll:

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


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## woodsworth (27 Feb 2010)

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.


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## Benchwayze (27 Feb 2010)

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

John


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## Woody Alan (27 Feb 2010)

> 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


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## bignomis (27 Feb 2010)

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


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## big soft moose (27 Feb 2010)

bignomis":288ful7o said:


>



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


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## Escudo (27 Feb 2010)

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.


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## bignomis (28 Feb 2010)

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]


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## Jake (28 Feb 2010)

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?


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## Lons (28 Feb 2010)

Jake":1plmgsnv said:


> 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 pineappled off! - life's a puppy - can't afford a divorce!  :x :evil:


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## warrenr (28 Feb 2010)

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


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## woodsworth (28 Feb 2010)

> 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


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