Concrete slab costs ...

[pvr]

Right, new project - putting up another building which needs a concrete base.

Size is 7 * 7 meters, all soil to be left on site. Company quotes £5650 for the slab alone which seems expensive. Can anyone recommend a company in Sussex that can lay the base for a more reasonable figure? I always get told that you can build entire garages for about £2k or so, so would like to see if I can get at least the base for that ...

 

[RJS-Z4]

PVR I work for a design and build company and have great ties with the builder. He's currently in Aus on the Lions tour but will be back in 17 days, if you're in no serious rush I'll get a quote if you send me a few photos.

I can personally guarantee the quality of his work as I use him all the time.

 

[Z4coupebeaver]

Right, new project - putting up another building which needs a concrete base.

Size is 7 * 7 meters, all soil to be left on site. Company quotes £5650 for the slab alone which seems expensive. Can anyone recommend a company in Sussex that can lay the base for a more reasonable figure? I always get told that you can build entire garages for about £2k or so, so would like to see if I can get at least the base for that ...

Wow, that must be a very deep slab or a very expensive contractor. That's over £100/m2.

I'm just doing the sums on a 7x5 slab so it will be interesting how that compares.

 

[pvr]

No rush at all so no problems there.

It is an empty space next to an existing barn in my field, just flat grass at the moment. Would a picture of that help?

 

[PerryGunn]

Ridiculous price for a slab - you don't say what the building is for but assuming it's a straight-forward, non-insulated slab with reinforcement

Work out the basic price if you were DIYing and then go from there for labour costs

- you need a 7m x 7m x 30cm hole (this would give you something easily strong enough for parking cars/tractors on)
- Half fill with hardcore/MOT, then blind with sharp sand and whacked down

- hire a mini-digger for about £120 for the weekend and it would take less than a day to scrape out the 7m x 7m x 30cm rectangle
- Whacker plate £20-£30 for weekend
- You can either put down a sub-base of Type-1 MOT or hardcore (I'd probably use recycled crushed concrete) then blind them with sharp sand either way total cost should be < £200
- Optional membrane - depends on building application so say up to £100
- Optional Reinforcement grids & top hats < £100
- 7m x 7m x 150mm -> 7.35 cubic meters of concrete S2 mix for reinforced bases @ roughly £900-£1000 from a mix-on-site company

That would give a (very) rough figure in the region of £1600

I've done this sort of thing myself and it would take a couple of weekends to get it all done - nice to have a second person for the concrete leveling and you may find that a normal 7m slab needs an expansion control joint but you can probably get away without if reinforced (all depends on application)

 

[pvr]

It is only going to house a timber building !!

 

[pvr]

I've done this sort of thing myself and it would take a couple of weekends to get it all done

When can you start - you are local - right?

 

[PerryGunn]

I've done this sort of thing myself and it would take a couple of weekends to get it all done

When can you start - you are local - right?

If I had more time, I'd gladly help you out - unfortunately, I have my own back garden that needs landscaping this summer (assuming we have a summer)

If it's a wooden building, you'll probably want the slab to end up a few inches above ground level to prevent water pooling so you'll need build a wooden form to retain the concrete when it's poured - again very easy. When I did my driveway slab, I dug some trench footings around the edge and built a retaining wall to hold the concrete, I used concrete blocks as they weren't going to be visible but you could do it in red or blue engineering bricks and it would look a lot nicer than the edges of a plain concrete slab

 

[pvr]

All good info, thanks

Always a bit disappointing when a company you have used twice applies M tax to a new project

 

[PerryGunn]

All good info, thanks

Always a bit disappointing when a company you have used twice applies M tax to a new project

I don't know the company you're using but, sometimes, if building companies are very busy, they quote high as they don't like to turn people away but may have to obtain additional people to fulfill a job.

One of our friends was a director of a company that supplied short-term staff to the building industry and the effective 'cost' of these people to the building company was much higher than their own workers but they could have them for anything from a day to several months depending on workload. At the end of the day it was the customer that ended up paying.

 

[dr_john]

I had a 3m x 4m concrete slab done for a summer house a couple of years ago, they did a good job with hardcore base etc for £800.

You have approximately 4x more area than me, so pro rata I would say about around £3000 would be more like it.