Just been left high and dry (literally!) with hardcore that is too high. Now what???

[oranjeboom]

Admins, please move thread to another area if this isn't the best area!

Okay, I had contractor to come and dig up my old slab (100mm) and then proceed to remove a further 375 of soil. They then barrowed back in 150-160mm of type 1. They proceeded to compact it with their wacker which IMHO was too small for the job. But they kept going....and of course they didn't get to the required 100mm compacted level. I spoke to the contractor and he said he would be back today (early!!!) and would come back with a decent whacker that they use for roads. I thought they'd use a roller for that, not a whacker but who am I to say what's best....

Anyway, looks like the £250 retainer that I kept back wasn't enough to get him back to finish the job off. The bar steward has not showed up and is not answering my calls. Should have retained a bigger amount but I stupidly trusted the man. And the two barrows and rake they left behind aren't going to make up for things. I could be livid, but I'm fairly used to it in this country that homeowners get shafted like this. It's a way of life. Just look at the TV shows that rely on these 'cowboy' trades. And trying to take things up via the small claims court is just not worth the effort and expense.

So rather than get angry about it, I'd like to channel any negative thoughts into getting the job finished. And rather than get someone else in, I'll probably tackle the 88sqm myself. The small whacker they had was clearly not up to the task of crushing the 160mm down to 100mm. Think they used a 450mm plate (83kg). What do I need to get this done? In most places I will need to go down another 40-50mm. Would this baby do the job? http://www.jewson.co.uk/tool-hire/compaction/plate-compactors/products/2530/reversible-plate-compactor-500mm/

Do-able in a day?

I need to go down another 50mm as otherwise I won't get sufficient EPS under the new floor slab.And that was the whole flamin' point in going down do deep in the first place Mr R. BlXXXMAA of AXXXFXXW, you !"£%^&*()_+ !!!!!!!  Can't wait to write up my review on MyBuilder......

 

red pen = excavation level, white marker = 100mm compaction level, red marker = top of hardcore

bloody uneven too!!

not really clear, but room centres are a lot higher too.

Ideally I don't want to remove any hardcore and then compact and then add a bit back in, compact......

Advice, options? No replies on cowboy tactics, my gulliibility etc pls. That's another thread-starter....

Edited June 26, 2016 by recoveringacademic
Photos added, descriptions: tags tidied up

[AliG]

Googling this suggests that type 1 will compact down around 20-25% from the original depth. I don't think you could get 150-160mm down to 100m.

People suggested to lay 130mm if you wanted to compact down to 100mm.

[oranjeboom]

10 minutes ago, AliG said:

Googling this suggests that type 1 will compact down around 20-25% from the original depth. I don't think you could get 150-160mm down to 100m.

People suggested to lay 130mm if you wanted to compact down to 100mm.

That was my fear too. And I had reservations that they'd added to much type 1 in the first place. And that makes sense as the 18t originally shipped in was not enough for them! Cowboys!

[Declan52]

80mm down to 50mm and then same again if it's a small Wacker. It would need to be a very large Wacker to get it down from 160 to 100mm. 

Think you are going to have to remove some hardcore and leave it maybe 10-20 higher than you need and then wack the shat out of it. Go up and down and then side to side with the Wacker when you are doing it. You need a fine sand or quarry dust to get it snooker table level. 

[oranjeboom]

11 hours ago, Declan52 said:

80mm down to 50mm and then same again if it's a small Wacker. It would need to be a very large Wacker to get it down from 160 to 100mm. 

Think you are going to have to remove some hardcore and leave it maybe 10-20 higher than you need and then wack the shat out of it. Go up and down and then side to side with the Wacker when you are doing it. You need a fine sand or quarry dust to get it snooker table level. 

Thanks Declan. Not what I want to hear really.  I think I will try and get that big whacker (140kg) and see what it does. I really don't want to extract all down to 80mm and whacker layer by layer. Hopefully a big'un will do it.

@Onoff - what are you doing next week???? 

[Jeremy Harris]

Been there, done that, in our case it was the hardcore for the temporary access, that was supposed to end up as the drive base later.  Last day of the work, the ground works chap chucked in tonnes more than was needed and couldn't compact it to the right level, then walked off the job and invoiced me for the final stage payment before I'd noticed that the access was far too high. 

The first truck that tried to get up it (a skip lorry with an empty skip), really struggled and rutted up the surface badly.  I had the foundation team coming in at the start of the following week, who needed concrete truck access, so I hired a minidigger for a day and started digging out and relocating the hardcore to one side.  It took me a whole day and in places I dug out a metre in depth and still hadn't reached the terram that was laid under it!  It was supposed to be a 200mm thick layer, graded to the levels on the plan.

Later, when we put in the drive drainage crates and laid the proper drive we had to take out around 170 tonnes, a fair bit of which was unwanted crushed concrete that the main ground works contractor had laid in excess.  At a guess I reckon there was a good 30 tonnes too much, around two tipper truck loads.

[Onoff]

11 hours ago, oranjeboom said:

Thanks Declan. Not what I want to hear really.  I think I will tray and get that big whacker (140kg) and see what it does. I really don't want to extract all down to 80mm and whacker layer by layer. Hopefully a big'un will do it.

@Onoff - what are you doing next week???? 

She'd kill me if I started helping anyone else! Maybe when the divorce comes through.....

Just a thought, could you roughly calc the volume that needs removal and dig a "big hole" in the middle of the area of a similar volume. Then rake in towards the hole. Just thinking having the hole might help the "mass" collapse in.

EDIT: I've just reread the OP. 40-50mm down? If you remember my floor, prior to concreting I ran a couple of level rails down the opposite walls. Maybe do that. Get the pick out and loosen with the pick, rake & shovel keeping an eye on your guide board.

 

[Tennentslager]

Phone the local TA and offer the troops some hard cash. 

Beer money for a few hours of many hands and all that...

Maybe?

[oranjeboom]

4 minutes ago, Tennentslager said:

Phone the local TA and offer the troops some hard cash. 

Beer money for a few hours of many hands and all that...

Maybe?

They'd probably do a better job than aforementioned contractor.

17 minutes ago, JSHarris said:

 

Later, when we put in the drive drainage crates and laid the proper drive we had to take out around 170 tonnes, a fair bit of which was unwanted crushed concrete that the main ground works contractor had laid in excess.  At a guess I reckon there was a good 30 tonnes too much, around two tipper truck loads.

I recall reading that in your blog Jeremy. Not just me that gets shat on then! "better to chuck too much in than too little" seems to be the approach here. Did you re-use the 30t elsewhere?

 

20 minutes ago, Onoff said:

She'd kill me if I started helping anyone else! Maybe when the divorce comes through.....

Just a though, could you roughly calc the volume that needs removal and dig a "big hole" in the middle of the area of a similar volume. Then rake in towards the hole. JUst thinking having the hole might help the "mass" collapse in.

More flack for me too from the boss tonight now doubt about the latest setback! Either way of removing layers will mean me having to shift barrow loads up scaffold boards out the front door and then having to make space out the front first. Just all a PIA!!

[Declan52]

Only way out of not digging out at least 40-50mm is to use less insulation in the floor.

How much had you planned to use??

How much have you left from the top of the hardcore to the bottom of your door frame??

I am removing wood chip off my sister's walls so digging hardcore out would be music to my ears. Only thing left to try and remove it is petrol and a match.

[Onoff]

A quickly installed level drag board will give you a reference. It will also let you see your progress when the going gets tough. The danger with attacking a big area as a whole is you'll jump about with no real plan, take too much out here, not enough there and be doing unnecessary work.

[Jeremy Harris]

18 minutes ago, oranjeboom said:

I recall reading that in your blog Jeremy. Not just me that gets shat on then! "better to chuck too much in than too little" seems to be the approach here. Did you re-use the 30t elsewhere?

What annoyed me was that I'd calculated the volume of crushed concrete needed to get the levels right, and when the firm quoted I questioned the cost of it (it seemed high) and they suggested I talk to their QS.  Their QS is the one who seems to have cocked up, and if I'd had the confidence to stand my ground and get them to reduce the quantity to the figure I'd calculated things would have been about right.

Sadly we couldn't re-use more than a couple of tonnes of it.  In fact I have a feeling that when we come to plant the two cherry trees either side of the drive entrance we may well need to lose another tonne or so of it, as I'm pretty sure those areas still have a fair depth of it that will need to be dug out and got rid of, then replaced with (expensive) topsoil.  The costs quickly add up with mistakes like this, paying for the stuff, paying to have it taken away and then paying again to have proper soil brought back.

[Ferdinand]

I am supposed to be on holiday, but I have just been settling in to the corner suite to which I have been upgraded (!) drinking my complimentary brandy (!!) in the Earls Court Hilton, which is a bit 1980s in brown style but comfy.

If you decide you need to dig some out, remember that you can get micro diggers that will go through a doorway that would speed you up. 88sqm sounds like quite an area.

Ferdinand

Edited June 18, 2016 by Ferdinand

[oranjeboom]

10 minutes ago, Declan52 said:

Only way out of not digging out at least 40-50mm is to use less insulation in the floor.

How much had you planned to use??

How much have you left from the top of the hardcore to the bottom of your door frame??

I am removing wood chip of my sister's walls so digging hardcore out would be music to my ears. Only thing left to try and remove it is petrol and a match.

I need to get 275mm EPS70 in, I could do less and then make up the difference with a thinner layer of PIR. But the cost of PIR vs wacker hire and 2days(?) work is probably going to be more. 

Woodchip? Just leave that on....I'm sure that will make a comeback eventually....

11 minutes ago, Onoff said:

A quickly installed level drag board will give you a reference. It will also let you see your progress when the going gets tough. The danger with attacking a big area as a whole is you'll jump about with no real plan, take too much out here, not enough there and be doing unnecessary work.

Yes, will just tackle it room by room and have the contractor's face projected onto the floor with an old projector I have lying around....as I wacker him to bits...

 

10 minutes ago, JSHarris said:

 Their QS is the one who seems to have cocked up, and if I'd had the confidence to stand my ground and get them to reduce the quantity to the figure I'd calculated things would have been about right.

Lesson for both of us Jeremy - trust our own calcs and double quibble everything!!

[oranjeboom]

7 minutes ago, Ferdinand said:

I am supposed to be on holiday, but I have just been settling in to the corner suite to which I have been upgraded (!) drinking my complimentary brandy (!!) in the Earls Court Hilton, which is a bit 1980s in brown style but comfy.

If you decide you need to dig some out, remember that you can get micro diggers that will go through a doorway that would speed you up. 88sqm sounds like quite an area.

Ferdinand

You just enjoy your flamin' brandy!! Maybe I should have a pint of the stuff here...

Not a time for me to start messing with a digger indoors - will probably take out the ceiling too!!

[Ferdinand]

it is always a good decision to have good brandy around.

But perhaps not before mini digging.

I think I agree this might not be a time to try something new.

Best of luck.

Ferdinand

[Onoff]

If you went for PIR could you shop around for seconds to offset the cost difference above EPS?

If you don't re-level / whack you're still going to have to fork out for finer aggregate to achieve some sort of near level.

[Declan52]

Level it out with sand like onoff done with a drag board end up with 250mm insulation or thereabouts. Use pir to get the u values up or get the pick out and get swinging, no other way out of it really.

[DavidFrancis]

250 or 275 mm of EPS. A difference of maybe just over 0.01 in your u-value for one element of your build. Would that affect your heating bill by more than a couple of quid per annum?

[Onoff]

1 hour ago, Declan52 said:

Level it out with sand like onoff done with a drag board end up with 250mm insulation or thereabouts. Use pir to get the u values up or get the pick out and get swinging, no other way out of it really.

I used sharp sand. Felt soft sand might "filter" down through the Type 1. If it had been REALLY out of level then I'd have probably used some form of grit.

[Ferdinand]

8 hours ago, oranjeboom said:

You just enjoy your flamin' brandy!! Maybe I should have a pint of the stuff here...

Not a time for me to start messing with a digger indoors - will probably take out the ceiling too!!

I did.

Burrrrrrrpppp !!!!

    

Bit footsore after about 7 gardens, mind.

I have had some further possibly useful, rather than flippant, thoughts during the day, which I will add later on this evening.

Ferdinand

Edited June 18, 2016 by Ferdinand
Update

[oranjeboom]

12 hours ago, Ferdinand said: have had some further possibly useful, rather than flippant, thoughts during the day, which I will add later on this evening.

Ferdinand

Still waiting Ferdinand ?

 

12 hours ago, Ferdinand said:

    

Bit footsore after about 7 gardens, mind.

 

Better have another brandy!

[Ferdinand]

Quote

Still waiting Ferdinand ?

Tokyo time. Innit .

Actually I had a cocktail (Susan's Sour something, with heaven knows what and 2 strawberries), a glass of wine and a 12 year old whisky. And a good snooze.

OK, earwig-o, earwig-o, earwig-o.

People have talked about using EPS a little thinner and having a little less protection, or using PIR (which costs very nearly the same "per u-value" as EPS. I would probably go PIR myself.

However, another option for your extra, which would avoid days of inside digging, is what we call "skirt" ventilation, where you insulate the outside of your foundations rather than the floor. I'll give a fairly detailed explanation in case you are not familiar. It would be easy if you are doing outside digging round the house, or would help with any damp you have rising in your walls, if you have that.

Skirt insulation is used as an extra when doing External Wall Insulation, when contractors tend to stop 150mm off the ground (leaving a huge cold bridge all the way round the house at the wall bottom), or when underfloor insulation cannot be retrofitted due to the floor being concrete or similar.

The technique is:

1 - Dig a trench round the house next to your wall, probably one section at a time, but ideally all the way to the base of your foundations.

2 - Line the wall side of the trench with EPS (say 100mm-200mm depending) to its full depth.

3 - Line the trench with fabric to stop soil getting in and clogging the drain.

4 - Put a French drain (perforated pipe - perforations are in the bottom half of the pipe are it lies in the trench covered in gravel leading to a soakaway).

5 - Fill with LECA (Lightweight Expanded Clay Aggregate iirc - somewhat insulative itself) or Gravel, fold the weed fabric over the top and finish the surface as you choose. If you have 200mm of EPS in the floor I think gravel may be OK, but make sure it is bigger gravel than the holes in your pipe.

EPS is the one to use for this as the performance of PIR deteriorates more if your drain gets clogged and it gets wet. Ideally you need a low water table, or your soakaway may not work, but if you have a high one some others may have relevant experience.

I use a 2ft wide trench, 5m lengths of soil pipe that I drill holes in, the best weed fabric I can find with generous overlapping on top just below the surface, level with a final couple of inches of gravel, and simply loose lay Pressed Council Slabs over the top to give a circum-house-path that can be easily removed should I ever need to maintain anything. In future when I build it will be tempting to put services in there in the gravel, but I have not considered that in detail yet.

Skirt insulation works by closing the peripheral cold bridge to the outside surface soil which is at outside temperature, and creating a far longer heatflow path. The heat escape route is closed off because the ground, once you get down a couple of feet, is warm all year round at perhaps 5-10 degrees centigrade. The piece of ground under your house would gradually heat up over time, and the benefits increase.

If you only do part of your periphery there will still be a benefit. I tend to add it in tactically whenever I dig near a house wall.

There is much discussion of this on the Green Building Forum, and a number of years' experience, and people like Steamy Tea can correct me if I have anything wrong.

Best of luck.

Ferdinand

Edited June 19, 2016 by Ferdinand

[TerryE]

Ferdinand, as I see it @oranjeboom has 3 remediation paths: (a) leave the wibbly high infill, levle and use a high U-value insulation, (b) dig out and relevel, (c) the external skirt option.

100mm of PIR might not be ideal but it will perform reasonably.

Depending on the total area digging out and rewacking might only be a couple of days work and if necessary hiring a minidigger to avoid the backbreaking work.

I would discount your external skirt option as it won't be as effective as the other two and is a major undertaking. 

So I would personally choose one of the first two, probably the second.  This underlines the wisdom of the slab makers approach (and they used a fairly small wacker plate BTW) whcih was to lay the hard core in 50mm layers and level (using laser) and whack down each layer then finish with 50mm sharp sand whack and top up to final level using screed bars.  I 

[Declan52]

Dig 30-40mm of the top of the hardcore or an outside trench round the room perimeter, know what option I would pick. A few hours with a pick, shovel and Barrow and it would be done. Only the Lord rested on Sunday, if you believe in fairy tales, so get cracking!!