Piling mat - how to reduce cost

[Hilldes]

Struggling to control groundworks costs at present. I know that some of the greatest unkowns with a build are below ground, but generally I'm finding groundworkers either don't wish to quote or are quoting prices that I see as high - and collectively for all elements of ground works are much higher than I had budgeted.

 

Here is one example - the piling mat specified by the piling contractor. See attached specification. I've been quoted £8.5K for the excavation (moving spoil on site) and supply and laying 200mm of 6F2. Note the level of the 6F2 needs to be relatively accurate and will sit level with the top of the reinforced concrete ground beam that will link the piles.

 

Any ideas how I can bring this cost down. e.g. is this DIY-able by hiring a digger and dumber truck for a few days?

[Faz]

I had the same problem on groundworks - I don't know what is going on with these lads but suspect the furlow scheme has a lot to do with it to be honest.  Went out to 9 companies and not 1 came back with a price.

 

Hired in a chap on a day rate in the end to pull the foundations with a 23.5T machine who was fantastic. Where abouts are you?

 

We still have a problem on drainage made a bit worse as I have ripped the guts out of the groundworks package - easier to deal with I suppose as the problem is smaller. We will get it sorted.

[Gus Potter]

What type of piles are you using, size, type, predicted length etc.

 

How big a rig / type do you need? If you can take a step back then you can maybe make progress re temporary work matt design and how you can maybe incorporate this into the final design. Also, have a look to see if / how you may be able to recycle stuff as this can offset the matt cost.

 

As a word of encouragement it may not cost as much as you think, although a bit of a stinger up front.

[Hilldes]

Thanks @Faz and @Gus Potter based in Surrey and looking at options such as demolition contractor crushing the masonry from the bungalow we are demolishing on site to produce the 6f2. I hear that crushing on site can be noisy for the neighbours but this will need to be balanced with transporting rubble off site and transporting 6f2 back to site.

Much of the excavation will be required anyway as we need a 300mm void under the beam and block floor due to clay soil and oak trees - would only need to remove a couple of inches of the 6f2 to get the 300mm void.

 

Does anyone have experience of DIYing work like this with no previous digger driving experience? Any view on what size digger would be best? Would need small dumper as will need to drive across tree root protection areas.

Edited November 4, 2020 by Hilldes

[Dave Jones]

lets do some back of a fag packet math.

 

155m3 of dig once bulked is going to be 200-250m3 depending on what the ground is. That's 50-70 trips with a 6 ton dumper being loaded by a 5/8 tonner. 2 days if the dump isnt far.

 

Factor in at leaser 1.5 bulking factor for the hardcore 220-300 tons and hope it doesn't rain or you will be paying  to haul rain as well as hardcore loves to soak up water. 13-20 8 wheeler loads. 2-3 days depending on how good your hauliers are. assume they can dump on the pad so it doesn't have to be moved twice. Levelling and compacting (roller ride on) as they deliveries happen.

 

So a good weeks work, digger, dumper and roller on hire 5-800. hardcore loads round our way (recycled) 10-15 a ton

 

worst case

 

plant hire - £800

Fuel - £100

6F2 - £4500

Total - £5400

 

labour  3 people 5 days @ £200/day - £2400

 

total £7800

 

 

not much fat left for profit. Plus the builder is going to have the contacts in haulage to make it happen which you wont. 

 

A nice simple task though which if you can run a digger well and dig to a laser level so your not pulling out more than needed etc and have someone to run the dumper and roller at the same time you could save maybe half of the quote ? Depends on your timescales as well do you have much time before the piler arrives ? You don't want to be in a position where your not finished and have to cancel.

 

 

 

Edited November 4, 2020 by Dave Jones

[Gone West]

4 hours ago, Hilldes said:

looking at options such as demolition contractor crushing the masonry from the bungalow we are demolishing on site to produce the 6f2. I hear that crushing on site can be noisy for the neighbours but this will need to be balanced with transporting rubble off site and transporting 6f2 back to site.

We had our masonry crushed on site and it was noisy but I guess it depends on how built up the area is and how the sound is reflected around. Not bad around here.

 

 

[Hilldes]

Thanks @Dave Jones that is really helpful, I can see the logistical challenges now. Because of tree root protection we may need more like a 1 or 3 ton dumper which would be a lot of trips.

 

I'll see what we can do with the demolition contractor crushing the existing bungalow on site to reduce costs of 6F2 as that is the big ticket item. He's actually quoted me just an extra £500 to crush on site (which one on the groundworker's that did quote says is way too low as the crushing will take 5 to 6 days - but that is another story).

 

I'll also talk with the piling contractor about maybe reducing depth of the 6F2.

 

The point you make about schedule is really important - I can't delay the piling contractor once we have firmed upon their start date. While I'd love to play with a digger, I'm not sure that would be the best option for schedule alone. 

[Hilldes]

Thanks @PeterStarck I saw your crushing on site post a while back and was going to look it up again.

 

How big was the property you demolished to produce the 50 tons? Our is a 1950s bungalow with a 158m2 footprint, concrete slab and block and brick walls (blocks are the blue 'breeze' blocks).

 

It sounds like you needed a finer crush than us - I think our 6F2 is max 75mm chunks.

 

At least we'll be crushing in winter so people will have windows closed. Also taking Dave's numbers above for the number of truck loads we'd need to take the uncrushed masonry off site and transport 6F2 back to site, that would be a lot of truck loads on our small/quiet road.

[Dave Jones]

2 hours ago, Hilldes said:

Thanks @PeterStarck I saw your crushing on site post a while back and was going to look it up again.

 

How big was the property you demolished to produce the 50 tons? Our is a 1950s bungalow with a 158m2 footprint, concrete slab and block and brick walls (blocks are the blue 'breeze' blocks).

 

It sounds like you needed a finer crush than us - I think our 6F2 is max 75mm chunks.

 

At least we'll be crushing in winter so people will have windows closed. Also taking Dave's numbers above for the number of truck loads we'd need to take the uncrushed masonry off site and transport 6F2 back to site, that would be a lot of truck loads on our small/quiet road.

talk to your 6F2 supplier, they may take your rubble off you and crush themselfs. I did a deal on last build they delivered 1 load of crushed free for each 2 loads taken back. It doesnt really cost them much as they are running back to the yard empty anyhow and they have massive crushers to deal with it properly.

Edited November 4, 2020 by Dave Jones

[Gone West]

2 hours ago, Hilldes said:

Thanks @PeterStarck I saw your crushing on site post a while back and was going to look it up again.

 

How big was the property you demolished to produce the 50 tons? Our is a 1950s bungalow with a 158m2 footprint, concrete slab and block and brick walls (blocks are the blue 'breeze' blocks).

 

It sounds like you needed a finer crush than us - I think our 6F2 is max 75mm chunks.

 

At least we'll be crushing in winter so people will have windows closed. Also taking Dave's numbers above for the number of truck loads we'd need to take the uncrushed masonry off site and transport 6F2 back to site, that would be a lot of truck loads on our small/quiet road.

It was a timber frame around 7.5m square on brick plinth and concrete ring beam. On the back there was an old block cavity extension around 30m2 on concrete slab and footings with block internal wall. It was crushed to 50mm.

[Faz]

7 hours ago, Hilldes said:

Thanks @Dave Jones that is really helpful, I can see the logistical challenges now. Because of tree root protection we may need more like a 1 or 3 ton dumper which would be a lot of trips.

 

I'll see what we can do with the demolition contractor crushing the existing bungalow on site to reduce costs of 6F2 as that is the big ticket item. He's actually quoted me just an extra £500 to crush on site (which one on the groundworker's that did quote says is way too low as the crushing will take 5 to 6 days - but that is another story).

 

I'll also talk with the piling contractor about maybe reducing depth of the 6F2.

 

The point you make about schedule is really important - I can't delay the piling contractor once we have firmed upon their start date. While I'd love to play with a digger, I'm not sure that would be the best option for schedule alone. 

To be honest, if you are considering operating the digger you are going to have to go off and get a ticket to drive it on site - my telehandler course and ticket cost £1290 plus VAT and I imagine it would be much the same for a digger.

[Dave Jones]

1 hour ago, Faz said:

To be honest, if you are considering operating the digger you are going to have to go off and get a ticket to drive it on site - my telehandler course and ticket cost £1290 plus VAT and I imagine it would be much the same for a digger.

 

no you actually don't unless you want to sub out to Persimmons!!

[Hilldes]

The crunching munching machine is on site today...