Passive Slab- MOT type 1 hardcore suppliers

[dogman]

Hi all

i am in the process of sourcing  30-50 mm diameter  MOT TYPE 1 Hardcore stone (non-recycled aggregate material) for our house,to go under the Slab. Has anyone found a good and cheap supplier in the South.

Not sure how much i will need but our house has a floor area of about 160 square metres.

If willing can you let me know how much did you need and what was the cost 

 

Thanks

[Mikey_1980]

We used recycled railway ballast, four MBC passive slab base, Hilliard was fine with this and it is what a few other people have used, we had 200 tonnes of the stuff for our base and it came in at 16.50 a tonne including transport costs.

[dogman]

Mike

 

Thanks. Was it a local company to us?

 Your house is somewhat bigger than mine what is your footprint? so i can get an estimate of how much i will need

 

Martin

[Mikey_1980]

Our floor area is around 270m2 and we were at a depth of around 300mm on the ballast. It came from Eastleigh train depot via Pritchett and sons. The other option we had was the waste from  the bottom of incinerators, that is the same spec and Hilliard was again fine with it, that was £8.50 a tonne delivered but at the time they couldn't get enough.

[jack]

If you go for railway ballast, make sure you specify the cleaned stuff (I think they steam clean it).  The stuff we got hadn't been cleaned and it was a bit greasy/grimy in parts.  Unfortunately, it was delivered and laid on a day I was at work, so it was too late to complain at that point.

[IanR]

We paid £16 / tonne delivered for Type 1 from SRC Aggregates.

 

If I remember correctly it's just under 2 tonne per cubic m. so we used about 170t for a 465 sqr. m . slab at 180mm thick.

 

BUT, we actually used more than that as we extended out beyond the slab for the width of the scaffold so that there was hard-standing for the scaffold to sit on. The scaffolders insisted on hard-standing (although it didn't need to be type 1), and most will be pathways and patios at the end.

[Mikey_1980]

58 minutes ago, jack said:

If you go for railway ballast, make sure you specify the cleaned stuff (I think they steam clean it).  The stuff we got hadn't been cleaned and it was a bit greasy/grimy in parts.  Unfortunately, it was delivered and laid on a day I was at work, so it was too late to complain at that point.

 

We were lucky ours was coming straight out of the washer into the trucks so when rolled and compacted and dried it was rock hard as we  found when digging drainage pipes for the rainwater drains.

[IanR]

14 hours ago, dogman said:

i am in the process of sourcing  30-50 mm diameter  MOT TYPE 1 Hardcore stone (non-recycled aggregate material) for our house,to go under the Slab.

 

Are you going with an MBC slab? I may be remembering this wrong from when I was considering the same, but doesn't TSD specify "no fines" in the compacted aggregate. If so I thought Type 1 was not suitable.

[TerryE]

Apparently it depends on the underlying soil type.  For clays Hillliard will specify a no-fines type, but for free draining soils such as sands, he might specify Type 1

[jack]

Interesting.  We're on almost 100% sand and he specced no fines.

[TerryE]

@jack, I am just going by another member who got an MBC warm slab recently on sandy soil and according to him Hilliard spec'd Type 1.  We were  told to have no fines also, and used crushed gravel, but the team suggested that we use type 1 for the last 50mm stone layer as this made it a lot easier to lay the blinding sand layer.

 

[jack]

Yes, I remember the post.  Just making the point that there may be more to it than being on sand.  I don't doubt that what Hilliard specs will work - my limited understanding of this type of system is that it's pretty robust, and there may be several ways of deep-exfoliating the feline.

[IanR]

Mine is an AFT Engineered, insulated raft, on clay with minimum load bearing capacity of 120kN/m2(mostly + 400) and AFT specifies Type 1 for the compacted aggregate, and uncompacted, no-fines, pea shingle for the blinding. Drainage is specified all around the perimeter, but I think that is also the case with a TSD engineered raft.

 

Both options clearly work, just need to ensure you follow the spec from the respective engineer @dogman to ensure their insurance covers any issues.

[PeterW]

Has anyone got a ballpark range for their build up of a passive floor slab per square metre ...?? Just interested to compare the different systems

[Mikey_1980]

So our cost based on excavation, laying of drainage pipes and supply and laying of the sub base for MBC came to £25 per m2 this excludes any demolition or disposal costs.

[PeterW]

Thanks @Mikey_1980 

 

Did MBC break out the price of the insulation / floor slab in their pricing or was it a package ..?

[Mikey_1980]

They didn't break it out but I didn't ask them to either I am sure they would be happy to though.

[IanR]

3 hours ago, Mikey_1980 said:

So our cost based on excavation, laying of drainage pipes and supply and laying of the sub base for MBC came to £25 per m2 this excludes any demolition or disposal costs.

Could you clarify what's included in the £25/m

 

When MBC quoted on mine,  as part of a foundation and frame package, they wanted drainage already in and sub - base down, compacted and level, they were then going to lay the blinding, EPS, Steel, UFH, pour the concrete and power float, all for slightly over than £160/m2

 

 

[Mikey_1980]

Sorry the above wasn't for the MBC base, this was for then ground works ready for MBC to lay the foundations. I have no idea what the foundation cost was per m2, the total package cost from MBC was around £420m2 and worth every

penny.

[dogman]

Thanks everyone i now have something to work with

 

We are on hard chalk although until demolition i will not be sure. 

 

All recent work around the old house has hit chalk after about 300mm with a hard hogging on top of this and according to BC is about as good as it gets.

 

MBC have asked for clean non recycled type 1 if the conditions are good

[Silage]

Opening up an old thread but does anyone else have an MBC slab cost per m2? As per @IanR above? I've got a 70m2 extension priced up and the initial MBC quote seems expensive. 

 

Edited June 9, 2017 by Silage

[TerryE]

You have to be careful with MBC not to compare "apples and oranges"  MBC typically do a passive slab power floated to FFL with the UFH included for a relatively small add.  With a more traditional builder you'll pay for base slab, insulation, UFH, top screed.

[Barney12]

7 hours ago, TerryE said:

You have to be careful with MBC not to compare "apples and oranges"  MBC typically do a passive slab power floated to FFL with the UFH included for a relatively small add.  With a more traditional builder you'll pay for base slab, insulation, UFH, top screed.

 

Yes I would agree. I think the UFH element for us was only £1,200 inc labour and materials. 

As you say start adding the screed to a traditional floor etc and it all adds up.

Of course the problem is MBC don't (or at least didn't with us) separate out the foundation cost from the frame.

 

[Silage]

@TerryE and @Barney12 thank you. I'm aware of the benefits and buy into them. I have a separate quote of £15.5k from MBC which seems outwith what I have read in this thread and other threads on this forum. Based on the range that I have gathered here I expected  between £7k for a basic slab to £10k for the full monty. Slab is one level and a 7.5m x 9m box. Visiting MBC next week so I'll discuss. Of course I'll be clobbered for Vat as it's an extension albeit a  'standalone build ' joined by a link to the existing cottage so I'm keen to minimise cost. 

 

Has anyone polished the slab to use as final floor finish? Would that require a different mix?

[Jeremy Harris]

I had several prices for an insulated foundation, from suppliers like Isoquick, Kore, SuperGrund.  All were around £10k to £12k approximate installed cost for 80m², back in 2013 when I was getting prices.  It was very difficult to compare prices, as all were based on different provisions, so I had quotes ranging from about £6k to about £8k, but these all left out big cost elements.  Some included SE fees, some didn't, none included the concrete cost, none included UFH pipes in the slab, some included the steel, some just provided a steel spec, none included labour or the ground prep and none included plant hire or waste removal.

 

We went with MBC, because the total risk was massively reduced by having the same company supply and install the foundation and supply and erect the whole house.  At a guess I'd say there was probably a 5% to 10% reduction on other costs from this, as they provided all the plant, crane, materials and did the installation, complete with UFH pipes.  I don't have a cost breakdown for their quote, so don't know what the slab cost was, but would guess that it would be at the upper end of the prices I had from other suppliers, but when you take account of all the included costs they were probably cheaper.