# Workshop Floor



## Bongodrummer (23 May 2011)

Hi Guys, 

We are in the process of converting an old barn into a workshop and are about to put down the concrete floor. It will be going onto shale with hardcore on top, and be 150mm thick. The paln is that the workshop will have a number of reasonably big machines - some woodworking but also some metal working machines. Some of these will be quite heavy, at least 500kg, so the guys who we are looking at getting the concrete from suggested 'CP35 mix' which is supposed to be very strong, and adding polymers (that give a similar effect to adding lots of glass fibres in that they strengthen it further). The polymers were only £5 per cubic m extra, so we will probably go for that (anyone have any experience of these?). 

Anyway, the question is, should we add regular farm pig netting to the concrete slab to try and strengthen it up? We have a mass of it just sitting about from some recent fencing jobs and could shove it in there as a sort of poor man's rebar. Some of the rolls are better than others - some have bits of rust - would including these be disastrous? Moreover, would the zinc coating on the rest of it react in any strange ways with the concrete? I have googled to try and find out if other people have done this, but not much luck, so I would be grateful for any input on this...


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## miles_hot (23 May 2011)

Don't know...I thought that rusting stuff was a good cause of cracking concrete but maybe that it only when the concrete has already started to leak and the rebar rusts as a result. After all rebar which goes in isn't exactly free of rust


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## Bongodrummer (23 May 2011)

Yeah, agreed, the stuff you see builders putting in is typically covered in surface rust :? The pig-netting we have is in comparably good nic I suppose. I wonder about the zinc/ galvanised coating and cement combo though.


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## Dibs-h (23 May 2011)

Bongodrummer":3bef1sh2 said:


> Hi Guys,
> 
> We are in the process of converting an old barn into a workshop and are about to put down the concrete floor. It will be going onto shale with hardcore on top, and be 150mm thick. The paln is that the workshop will have a number of reasonably big machines - some woodworking but also some metal working machines. Some of these will be quite heavy, at least 500kg, so the guys who we are looking at getting the concrete from suggested 'CP35 mix' which is supposed to be very strong, and adding polymers (that give a similar effect to adding lots of glass fibres in that they strengthen it further). The polymers were only £5 per cubic m extra, so we will probably go for that (anyone have any experience of these?).
> 
> Anyway, the question is, should we add regular farm pig netting to the concrete slab to try and strengthen it up? We have a mass of it just sitting about from some recent fencing jobs and could shove it in there as a sort of poor man's rebar. Some of the rolls are better than others - some have bits of rust - would including these be disastrous? Moreover, would the zinc coating on the rest of it react in any strange ways with the concrete? I have googled to try and find out if other people have done this, but not much luck, so I would be grateful for any input on this...



I get the impression that the folk supplying the concrete are a mobile batching wagon outfit. CP35 is their equivalent to C35 which is what's spec'd for commercial jobs (car parks, etc.)

For a concrete floor - it's way overkill. I'd reduce the spec to say something like C20 (or CP20 in their case) and add at least 1 layer of mesh 50mm up from the bottom - sat on proper spacers. If you are mega worried - you could always add another layer. Can't quite remember the spacing\spec of mesh - will ask my SE mate when I speak to him later this week.

Personally - I would use premix concrete (i.e. ReadyMix, Lafarge, etc.) and specify pump grade and get a pump firm in. I'm not referring to a Schwing type pump - there are others, where the pipes lay on the floor, etc. Going rate seems to be around £250-£300. Best money you'll spend and it'll be pumped in, in less than 30 mins, giving you plenty of time to tamp and float if you wish.

The batch-on-site ones - if it's a reasonably large area - probably start going off, before it's fully laid. Polymers, etc - sounds like marketing speak to me.

My 2c worth

Dibs


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## Bongodrummer (23 May 2011)

Hay Dibs, thanks for this. It was going to be ready mix style delivery... 



Dibs-h":3uatywze said:


> For a concrete floor - it's way overkill. I'd reduce the spec to say something like C20 (or CP20 in their case) and add at least 1 layer of mesh 50mm up from the bottom - sat on proper spacers. If you are mega worried - you could always add another layer. Can't quite remember the spacing\spec of mesh - will ask my SE mate when I speak to him later this week.
> Dibs



When you say mesh, do you mean proper rebar stuff, or the pig-netting I mentioned?


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## Dibs-h (23 May 2011)

Bongodrummer":24txmdie said:


> Hay Dibs, thanks for this. It was going to be ready mix style delivery...
> 
> 
> 
> ...



Yes proper rebar sort of stuff, such as







Dibs


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## Bongodrummer (23 May 2011)

So you are basically saying rebar is more important than the mix strength, right? That is likely to up the price quite a bit though :?


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## Dibs-h (23 May 2011)

Bongodrummer":32edb8gw said:


> So you are basically saying rebar is more important than the mix strength, right? That is likely to up the price quite a bit though :?



The mix strength is important - but it isn't the end all and be all for a concrete structure.

For your application - I believe (and I believe the calcs would prove it) C35 is way overkill and without rebar - C35 or even C50 wouldn't stop localised cracking.

I'm building (shortly) a new garage with a basement. The garage floor\basement ceiling will be cast in situ. To hold a car on the deck, a 2 post lift weighing 1T (metric) and a 1 car in the air. That's spec'd at C35. Your loads are minor compared to that. So why would a none structural floor require C35? With or without Polymers.

HIH

Dibs


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## bosshogg (23 May 2011)

Hi Bogo,

Specs for concrete are wide and varied, But generally what your doing, converting a barn into a workshop, and your description of the floor build up (pre conc.) is OK, just one word though, is this inclusive of a dpc course?

General flooring for barns, sheds, garages and the like, look for C20 conc at say 150 _ 200mm, indeed you can come down to 100mm and still have a good floor,for floors where heavy weight bearing and appearance are to be considered C35 is better. as for the mesh it depends on the thickness of the steel rods making it up, sound though like you are using a interweave style of mesh, and for that reason I would recommend not using it at all. The idea of the welded mesh used in reinforced conc. is to provide a stiffener for the conc. that will also distribute the load, in your case as this is a roll the stiffness would be missing, what you could do though is get some 9 _ 12mm rebar and wire fix on your roll of galvanised mesh say every 200mm or so, the bars should be set @ 600mm approx. If all this sounds a bit to much work, go for the propriety steel mesh, overlap by 300mm at any joints (all directions) and basically the 50mm clearance from the ground advice given is correct, you get spacers for this. 
Now where you are putting in heavy machines what you should be going for is mass, most often called footings, mass in the concrete will absorb vibration and provide a solid foundation for the machines, this applies both to woodworking and metal working machines but more so too the latter. there is no use installing say a metal turning lathe on a unsubstantial floor then wondering why it's inaccurate, that goes for all the other machines as well, dampening out vibration is one of the most essential factors for machines too work properly. How large are the machines intended to be installed? do they have feet where the bolts will be inserted through into the conc?? this could allow you to plan the floor space and put in machine footings say 600mm deep. Simply dig 450mm below the proposed floor excavation (assuming this is boulder clay, no shuttering required) infill as per your floor build up, make up some rudimentary reinforcement cages wire to your mesh reinforcement and pour. 
Polymers are specified where there is a reason, as you don't appear to have a reason why add them, you might require a retarding agent though depends how quick you can get it down, normally retarding agents are inclusive in the costs...bosshogg



> You can't solve a problem using the same thinking that created it...A.E.


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## Bongodrummer (23 May 2011)

Hay bosshogg.

Im going to go ahead and assume 'Bogo' was a typo :mrgreen: . 

Thanks for the reply! Interesting stuff. Looks like there are lots of options here. Although what you say about adding mass to the spots where machines will be makes complete sense to me, it seems like a big step to 'solidify' the shop layout at this stage. I was imagining a bit more flexibility - sort of see how people, particularly me, use things and adjust positions as we go. Not that easy to move one of these big machines I know, but... 

I suppose the two biggies will be the lathe (something like this: http://www.axminster.co.uk/axminster-sieg-cq6230b-910-metal-turning-lathe-prod570771/) and the milling machine (something like this http://www.axminster.co.uk/axminster-axminster-rf40-universal-mill-prod21300/). 

I notice that both the stands are sheet metal anyway which will not help with vibrations , so maybe I would be better off retrofitting some concrete blocks inside the stand, than I would be making a deep pad, given I might want to move it at some point :? 

Oh, one last thing - In terms of the polymer, the reason to specify was basically cost, we were advised that we might be able to do without the rebar if we had polymers added? 

Looks like I will have to check out the prices of rebar...Thanks again for your thoughts on this - kinda important to get the floor right!


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## bosshogg (23 May 2011)

Bongo,

Iv'e been in the business for more years than I care and I aint never come across a polymer that replaces the steel mesh, I have seen polymers that have altered the slump, curing time, waterproofed the finish, allowed for the thinnest of screed out retarded the setting and curing times, but again not one that replaces the reinforcement steel. You are in the right location for an alternative to concrete... hempcrete which has some amazing properties worth checking out. Your contact there would be Tyˆ -Mawr Lime Tyˆ Mawr, Llangasty, Brecon, Powys LD3 7PJ Tel: 01874 658000 Fax: 01874 658502 a lady by the name of Helen was very informative to me last year...bosshogg


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## chris_d (23 May 2011)

I recently used C30 concrete incorporating 0.91kg/m-³ of Fibrin 23 polypropylene fibres over a suspended 'beam and polystyrene panel' flooring system. The fibres replaced A142 steel mesh, acting in a structural capacity (spread point load) and to prevent surface cracking whilst the concrete hardened.

However, that was for a domestic floor system with assumed light loading. Your structural engineer / competent person should be able to advise appropriately on the basis on your particular loading characteristics (current and future) and if really helpful, specify a number of options on the basis of cost.

HTH,
C


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## Bongodrummer (23 May 2011)

Ah - "polypropylene fibres", thanks Chris, that may have been what they were suggesting actually, oops  

Hempcrete :shock: Now that's an idea worth looking into. I know very little about it, but isn't it usually a bit more lightweight? Maybe less appropriate for workshop application - as you said mass for damping is important ??
Will have to look into this - any quick heads-up on a cost comparison with regular concrete?


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## chris_d (23 May 2011)

For 3cu.m of C30 with fibres from Tarmac Ltd on 28-Aug-2010 = £293.62 + VAT.

For 6cu.m of GNE3 from Tarmac Ltd on 7-Aug-2010 = £400.00 + VAT


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## Lons (24 May 2011)

I find it difficult to accept that the polymers are an alternative to the welded mesh sheets which as already stated, spread the load of the concrete. I rarely lay a floor these days without mesh as the cost relative to the job is minimal. last price I paid for 3.6 x 2.0 x 9mm was around £15 +vat per sheet. As said, spaced 50mm off the bottom, overlap around 300mm and preferably tie overlaps with soft wire.

You should always put in a DPM and make shure the readymix supplier knows the concrete is to have reinforcement mesh.

You didn't say whether you will be putting floor insulation under the concrete but might be worth a thought if the rest of the barn is to be insulated as it would make a difference to comfort and heating costs.

Pig netting is too thin, too flexible to give any benefit IMO

Bob


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## tomatwark (24 May 2011)

Lons":3t5nvohd said:


> You should always put in a DPM and make shure the readymix supplier knows the concrete is to have reinforcement mesh.
> 
> Bob



A DPM is a must I know a couple of people woh have built workshops and not bothered, thinking as it is a workshop it does not matter.

They have regreted it since as they have had probs with damp workshops, timber that does not stay stable and machinery that goes rusty.

Tom


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## Dibs-h (24 May 2011)

Lons":3ke5cbkj said:


> I find it difficult to accept that the polymers are an alternative to the welded mesh sheets which as already stated, spread the load of the concrete. I rarely lay a floor these days without mesh as the cost relative to the job is minimal. last price I paid for 3.6 x 2.0 x 9mm was around £15 +vat per sheet. As said, spaced 50mm off the bottom, overlap around 300mm and preferably tie overlaps with soft wire.
> 
> You should always put in a DPM and make shure the readymix supplier knows the concrete is to have reinforcement mesh.
> 
> ...



When my foundations (shop) were designed - the recommendation by the SE was for the mesh to overlap by a min of 500mm, not 300mm. Admittedly I was using A252 mesh, and I suspect he wanted the mesh to overlap by 2 cells as opposed to one.

I'm seeing him later this week so will make a note to bring mesh overlap up in the conversation.

Dibs


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## Bongodrummer (24 May 2011)

Thanks for all the input guys. It looks like the ideal would be C35, overlapped rebar (maybe even 2 layers at different heights) _with _polypropylene fibers, a DPM and some insulation :shock: 

We hadn't even started thinking about insulation, we were just sort of ignoring it in the floor thinking it would not be a cost effective place to focus on - anyone got any advice or experience on thicknesses/materials/cost/what to avoid etc. Most insulation is quite weak and as its a floor that's got to limit the choices quite a lot right?
Thanks again,


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## Dibs-h (24 May 2011)

Bongodrummer":148fbax2 said:


> Thanks for all the input guys. It looks like the ideal would be C35, overlapped rebar (maybe even 2 layers at different heights) _with _polypropylene fibers, a DPM and some insulation :shock:
> 
> We hadn't even started thinking about insulation, we were just sort of ignoring it in the floor thinking it would not be a cost effective place to focus on - anyone got any advice or experience on thicknesses/materials/cost/what to avoid etc. Most insulation is quite weak and as its a floor that's got to limit the choices quite a lot right?
> Thanks again,



Sorry to be picky - but that's if money is no object, which I suspect it isn't.

I'd give the fibers a miss - can't see the need for them.


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## Bongodrummer (24 May 2011)

Dibs, 
agreed about the cost issue :? 

I cam across this article (http://www.ljmu.ac.uk/BLT/BUE_Docs/labib.pdf) yesterday, that was quite positive about the benefits of added polypropylene fibres. Although I can't find out where this was published (may have easily been 'commissioned' by fibre manufacturers for all I know), but it has an academic gloss  

Either way, for just £5 per cubic metre extra (we are only talking 7), doesn't it seem worth it?


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## Mcluma (24 May 2011)

You need to start at the bottom

100mm hardcore - compacted - 
sand 25-30mm - compacted -and as flat as a pancake - this is important otherwize your celotex isn't properly supported
membrame
celotex 100mm
reinforcement (rebar)
150mm concrete 

make it lovely wet so it goes in easy and leveling is a breeze

I normally have no leveling to do at all - but you to do tamping to get air out and the water to the surface

When you order the concrete tell them its for a garage then they will make it more stronger

success


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## Dibs-h (24 May 2011)

Mcluma":2y0w3n7v said:


> You need to start at the bottom
> 
> 100mm hardcore - compacted -
> sand 25-30mm - compacted -and as flat as a pancake - this is important otherwize your celotex isn't properly supported
> ...


Agree


Mcluma":2y0w3n7v said:


> When you order the concrete tell them its for a garage then they will make it more stronger
> success


Disagree - always spec the concrete. RC35 in this case. Spoke to my tame SE today and he states that for floors over 6", RC35 is required, when reinforcement is used. For < 6" could easily use RC30 as well - worth getting a price on both.

Dibs

p.s. When doing my build, one of my SE chums - stated that bringing the "fat" to surface reduces the structural properties of the concrete and one should only do enough tamping\vibrating to release the air and nothing more.


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## Lons (24 May 2011)

Dibs-h":25g9xvk0 said:


> Mcluma":25g9xvk0 said:
> 
> 
> > You need to start at the bottom
> ...



*Absolutely spot on * =D> 

You want it wet enough to flow, ( Make sure it is specified as that and not just add water on site which weakens the mix),which will allow minimum work in leveling and tamping. tamping or vibrating gets the air out, a float finish (if desired) brings the water to "cream" the surface and give you a finish. Personally I'd want my workshop floor to have a smooth finish which could be sealed and painted later.

I'd suggest that 9mm welded mesh reinforcement is plenty strong enough but you could go to 12mm if you want.
Either way - that's one hell of a good floor.

Bob


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## Bongodrummer (24 May 2011)

> I'd suggest that 9mm welded mesh reinforcement is plenty strong enough but you could go to 12mm if you want.
> Either way - that's one hell of a good floor.


 :lol: Sam my wife just read that over my shoulder, and proclaimed, "YEAH! One hell of a good floor, that's what we want damn it!"


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## Lons (24 May 2011)

Bongodrummer":108nzi0h said:


> :lol: Sam my wife just read that over my shoulder, and proclaimed, "YEAH! One hell of a good floor, that's what we want damn it!"



B***** should have written in a disclamer  I see a claim for damages coming on :shock: 

Word of advice - don't allow the boss to look over your shoulder - switch off / close the lid - whatever! She might imagine you're viewing porn, could even start checking your phone and emails 'cos she might suspect you're doing "a Ryan Giggs" - but can't be worse than the alternative you've just experienced :lol: :lol: :lol: 

I'd better explain that I'm a builder so work at home has a low priority. Taken me the last 2 1/2 years ( and still counting) to build an extension. New kitchen has been stacked up since December and only this week made a start. Will be done on a piece meal basis so loads of ongoing mess, dust and disruption. Just as well my wife has the patience of a saint. :wink: 

Bob


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## Bongodrummer (24 May 2011)

> 100mm hardcore - compacted -
> sand 25-30mm - compacted -and as flat as a pancake - this is important otherwize your celotex isn't properly supported
> membrame
> celotex 100mm
> ...



One question: what do we mean by hardcore? Are we talking gravel here? A certain grade of scalpings? or what?

We have plenty of shale knocking round, and the floor as it stands, has had a scraping/rough levelling with a mini digger, leaving bare shale. If this was compacted down would we still want the 100mm 'hardcore'?


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## Dibs-h (24 May 2011)

It's commonly referred to as MOT 1 or MOT.

http://www.smithsbletchington.co.uk/ind ... iew&id=101
http://reviews.wickes.co.uk/9987-en_gb/ ... eviews.htm

just to give you an idea - ring round for prices. I pay around £25 per bulk locally.

HIH

Dibs


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## Lons (24 May 2011)

Builders merchants might refer to it as hoggin, crusher or dolomite (yellow). Hoggin you would specify as say 20,40 or 80mm down to dust depending on the job.
If buying more than say 10 tonnes, it will be much cheaper to buy a bulk load from a quarry. 20 tonnes will be even better value if you can use it as a major cost is transport.

I doubt you would get away with shale on a dwelling but under a workshop floor??? You would know whether it's solid enough for you to be happy with.

Bob


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## Steve Maskery (25 May 2011)

I'm following this with interest, as I'm planning (head-planning, not paper-planning, yet) my next workshop. My current one has a concrete floor, but it is eroding in places, particularly where I wheel my TS about.
I was thinking that my next one will have a wooden floor. Is there a way of making the surface wooden but not springy?
S


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## condeesteso (25 May 2011)

re insulation - I'm not tech enough on this subject to know the structural / loading issues, but insulation would be a must for me. They use some kind of polystyrene sheet under concrete in houses?? but 500kg loads may be an issue. BUT the other point is damp membrane? - I am sure that it is impossible to make a workshop too dry (in the UK anyway) - moisture levels always an issue, esp in winter. So anything to make it as dry as poss is important I think.


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## Mcluma (25 May 2011)

Steve Maskery":35w4a1w5 said:


> I'm following this with interest, as I'm planning (head-planning, not paper-planning, yet) my next workshop. My current one has a concrete floor, but it is eroding in places, particularly where I wheel my TS about.
> I was thinking that my next one will have a wooden floor. Is there a way of making the surface wooden but not springy?
> S




To overcome this

have a nice smooth garage /concrete floor and put pvc tiles on it. these are industrial and are anti fatique and can hold weight over 1 ton, so no problems with wheeling the tools arround. they are interlocking so easy to lay down, they are water/oil and dust proof


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## Dibs-h (25 May 2011)

For a smooth surface - how smooth does a power float get it? Not meaning to hijack the thread - for my new garage floor, I am thinking about tiling the floor, which would be a damn sight easier if it was level and smooth.

Cheers

Dibs


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## bosshogg (25 May 2011)

Steve Maskery":560gshj1 said:


> I'm following this with interest, as I'm planning (head-planning, not paper-planning, yet) my next workshop. My current one has a concrete floor, but it is eroding in places, particularly where I wheel my TS about.
> I was thinking that my next one will have a wooden floor. Is there a way of making the surface wooden but not springy?
> S



Steve...put in a floating floor on top of your concrete one...seemloles_chk :lol:


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## Harbo (25 May 2011)

In this part of the world hoggin is an as-dug material and can contain clay which can get a bit messy when wet.
Crushed rock scalpings with some dust is much more stable and easier to handle if the weather gets bad.
It's angular and with the dust goes down very hard and rigid.

Polystyrene is very strong in compression but keep it away from diesel!
Providing it is restrained it will support very heavy spread loads - it is used a lot in Highway Concrete Bridge construction.
The suggested RC slab will certainly spread the loads. Concrete is weak in tension but strong in compression - the bottom layer of mesh is providing the strength as its under tension, the top layer mainly as anti-cracking (shrinkage etc.)

With the right concrete mix and power floats you can achieve a mirror finish.
Don't forget a spray applied curing membrane - prevents rapid drying of the surface and prevents hairline cracks.
You could use wet hessian or polythene sheeting but that would mark your surface.

Rod


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## bosshogg (25 May 2011)

Bongo, 

Re all the info that your getting, which I have to say is good, but you should try and concentrate on one system and one only, the choice of course is yours for the choosing. One thing Iv'e not seen so far is any mention of expansion joints, I have no idea the size of floor area you are attempting to pour, but you will have to include an expansion joint around your perimeter where you are meeting up with the existing walls, in the trade we normally use a 12mm bitumen fibre board which should be available from any builders merchant in your area




. Assuming your not covering the perimeter abutments you can also get a polythene joint sealer, that would go for the longest straight run also, if say it was 5meters one across the middle will do. You can cut an expansion across the middle with a Stihl saw but you have to make sure this section has the steel reinforcement stopped back before pouring, this is then filled with a polysulphide joint sealer, it's not as good, in my experience, but it does work...bosshogg  



> You can't help a man who doesn't tell you what he wants


 (homer)


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## Bongodrummer (25 May 2011)

Hi guys, thanks for all the input here, much appreciated.

Good point about the joints! The floor area is about 43sq metres 7.4m x 5.8m, though we may end up laying more in a bay in the front of the barn that leads to the proposed workshop area, if so that would be another 4 x 4m. Is that likely to need expansion joints 'mid slab'? When I get home I can post a diagram view... 

So insulation is sounding like a very good idea, given the difficulty of a retrofit. 

So far I think the spec is looking like 

100mm compacted MOT grade 1 scalpings
30mm sand blinding layer, well compacted and flat 
damp proof membrane
100mm celotex 
Steel reinfocment grid - may be going for 8mm, as builder says he already has some which will be cheap, if not 9mm - each grid overlapped approx 300mm and spaced 50mm up from the insulation. Leave room for possible expansion joints in the steel (did I understand this right?)
150mm C35 concrete with fibres (A 12mm bitumen fibre board expansion joint round the edge, to the block wall)
float finish (possibly power float?)
Spray applied curing membrane. 
cure.
Add possible expansion joints with still saw and seal. 

Thanks, B.


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## Lons (25 May 2011)

Harbo":1b2zuiun said:


> In this part of the world hoggin is an as-dug material and can contain clay which can get a bit messy when wet.
> Crushed rock scalpings with some dust is much more stable and easier to handle if the weather gets bad.
> It's angular and with the dust goes down very hard and rigid.Rod



Hi Rod - that's interesting to know. it's the old story of being careful what you ask for without clarification.
Cretainly wouldn't want clay or other contaminants in with the stone.

Your scalpings is presumably what we would buy here as "crusher" which is usually 20 or 40mm - dust.
I've used hoggin many times and never had clay among it so obviously different in this part of the world (or I've been lucky). Had 30 tonnes just last month - not as good quality or as well graded as crusher but ok.

cheers

Bob


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## Harbo (26 May 2011)

Bob just to clarify the Hoggin from this part of the world originates from old river beds and has rounded aggregate with differing proportions of clay fines/silt.
Fine when dry but when wet can get very messy.
Having said that a prized Hoggin (and getting scarce?) around here is called Romsey Gravel - it has a fine aggregate mix and much sort after in Conservation areas to give the authentic rustic gravel path look. 

Most of my experience is in building Highways and their associated infrastructure and the preferred choice of materials has changed frequently over the years. One thing that has never changed is the preferred use of MOT/DOT Type 1 Sub base which is a graded scalpings/crushed rock dust mix.  

Rod


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## Bongodrummer (26 May 2011)

Hi guys, 
So here is a rough diagram of what we are planning. The concrete floor will extend out under the base of the straw bale infill wall, providing a 'foundation of sorts. Given the lightweight nature, large surface area of straw bale, and that it will not be load bearing, we have been advised that this will not need any special foundations and can rest on the slab. We are planning a 2 bock high wall for that to sit on (just to minimise any possibility of damp getting at it (not shown).






So anyway, for that area (6.3x7.9m) how many expansion joint will we need? This datasheet (http://www.nrmca.org/aboutconcrete/cips/06p.pdf) seems to be suggesting that we want a joint at least every 4.5m, which would be a bit awkward because the bays are 6.3m. So looks like we are talking about splitting it into 4 sections of 3.15x 3.95m 
My concern is that 4 isolated concrete slabs will not be so effective at supporting the heavy machines and absorbing vibrations etc. Are the expansion groves 'all the way through'? Should the steel mesh be continuous or arranged so that there are breaks where the joints will be? Any input most welcome on this most welcome!


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## bosshogg (26 May 2011)

Rod[/quote]


Bongodrummer said:


> Hi guys,
> So here is a rough diagram of what we are planning. The concrete floor will extend out under the base of the straw bale infill wall, providing a 'foundation of sorts. Given the lightweight nature, large surface area of straw bale, and that it will not be load bearing, we have been advised that this will not need any special foundations and can rest on the slab. We are planning a 2 bock high wall for that to sit on (just to minimise any possibility of damp getting at it (not shown).
> 
> 
> ...


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## Bongodrummer (26 May 2011)

Thanks bosshogg.
We are only putting the concrete in the two walled in bays (the insulated area), and perhaps the part of the barn that leads to this area. Should the expansion joints be dowelled to hold the slabs in alignment, or is this overkill? I guess that way the slabs would have to be poured in at least two batches... 
Thins kind of thing?


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## Harbo (26 May 2011)

Until somebody came up with "Continuously Reinforced Concrete Pavements (no expansion joints) that was the "proper" way to do it. Usually cast every other bay to reduce thermal build up. One trick when nobody was looking was to use Denso tape instead of the expansion tubes.
Now concrete pavements have gone out of fashion as their surface produces too much tyre noise and they were not lasting their 40 year design life.

There is some interesting stuff in here albeit American: 

http://www.concrete.org/General/f302.1(04)Chap3.pdf

Rod


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## Bongodrummer (26 May 2011)

Hi Rod, 
Top quality link that - very detailed, thanks. Leaves me slightly befuddled by the number of options for different ways to joint mind :?


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## Bongodrummer (4 Jul 2011)

Hi guys, 
Just wanted to say thanks to everyone here who took the time to comment on this. 
My friend made a little time lapse of the actual pour day (and night), which I have posted on the blog. Despite being super rushed (we were preping the steel mesh right up to the point the first ready mix lorry arrived), it was all quite fun in the end, had a bunch of friends round to help, and did some manic barrowing  

Anyway, we went for saw cut crack control joints. What I am wondering is if anyone has any recommendations for a reasonably priced joint filler/sealer??? 

Also any views on finishing the concrete? Polyurethane paint? Any particular products good or bad?? 

Thanks.


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## bosshogg (5 Jul 2011)

Ask your concrete guys, they'll know the best available in the area, may even be able to supply you themselves. 
Remember concrete expands with terrific force when it's hot, make sure you cut the slabs sufficiently to allow for resultant expansion...bosshogg


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## Bongodrummer (5 Jul 2011)

hmm, we are the 'concrete guys', I think, or did you mean the ready mix company?


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## bosshogg (5 Jul 2011)

Ooops, yea the ready mix co. Then again if you were able to ask, and answer the question yourselves you wouldn't have posted it in the first place, would you?...bosshogg :lol:


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## Bongodrummer (5 Jul 2011)

Good point :lol: 
There just seem to be a LOT of products out there that would do the job... Just finding the right one...


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## Mcluma (5 Jul 2011)

I like the credits at the end of the film

especially about the concrete drivers. I have still to meet a nice concrete driver.


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## Bongodrummer (5 Jul 2011)

The first one was really nice. I think he was enjoying our mad dashing about with the barrows. The second one was just plain grumpy though.


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## Cegidfa (11 Jul 2011)

Hello Steve, sorry for the diversion Bongo.

I have just done this in my workshop build. I used Knauf Polyfoam floorboard extra - a non squashy insulating sheet at 35mm thick.
Over this I laid a glued, floating, ply floor. It is solid in use. The only moan that I have, is that I couldn't get T & G WBP 18mm ply,
so bought WISA plywood spruce floor, it is too soft, and the Record T/S and bandsaw wheels leave small tracks. To see it carried out, visit my 'Workshop build with a difference' , in Projects, about half way down Pg 15 onwards.
Be wary of using Kingspan/Celotex types, as they are designed for walls and as such are more 'squashy'. 

Hope that is of use, maybe the build could be useful too, in some way. I say that with trepidation, as you are a pro and I am a rank amateur :smile:

Regards...Dick.


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