Concrete base sunk after rain

larrymiller

So the base poured by the contractor for the pillars on my new slatted house are all after sinking or moving up on one side.. going to call him shortly, should he have to cover the costs involved in fixing this or am I going to have to.(pillars weren't up but the holes were drilled and levels taken by shed man)

Reggie.

larrymiller wrote: »

So the base poured by the contractor for the pillars on my new slatted house are all after sinking or moving up on one side.. going to call him shortly, should he have to cover the costs involved in fixing this or am I going to have to.(pillars weren't up but the holes were drilled and levels taken by shed man)

Any idea why they moved

larrymiller

Reggie. wrote: »

Any idea why they moved

The back fill was to soiley and not enough filling. And then it sank like a grave

Trasna1

larrymiller wrote: »

So the base poured by the contractor for the pillars on my new slatted house are all after sinking or moving up on one side.. going to call him shortly, should he have to cover the costs involved in fixing this or am I going to have to.(pillars weren't up but the holes were drilled and levels taken by shed man)

It depends on what was specified. If there was nothing called up to build up the levels on the drawings then you are on the hook.

Contractor should know better though. You don't put disturbed soil under foundations.

Reggie.

larrymiller wrote: »

The back fill was to soiley and not enough filling. And then it sank like a grave

That would be the builders fault so. Imagine if the shed was half built

mickdw

Am I right in saying he backfilled around the tank wall with that soil then just poured foundation pads onto it.
If so, that was never a suitable material and it's just lucky this happened now instead of when it was all built.
In my opinion this failure is not just a consequence of torrential rain, more a consequence of substandard work.
Who pays depends on what the actual deal was. If it was your decision to use that backfill and he is only Labour, Well It's Your Baby However If he is in there with contract to build the entire structure, it is his responsibility to use proper materials and workmanship - neither of which is present there so I'd be insisting on it all being removed, proper compacted stone fill used and concrete bases redone.

tanko

Even if it hadnt sank, thats no way to build a foundation for the pillars.
Surely it should be built with blocks down to the bottom of the tank before it was backfilled.

larrymiller

The contractor was brought in to do everything (apart from the shed).

The man himself wasn't here when they back filled it so maybe it was a mix up from the lads working for him.

He's a very good man with a great name around so not going to cut the back off him.

And yes I am extremely lucky the shed wasn't built as I would be up **** creek

larrymiller

tanko wrote: »

Even if it hadnt sank, thats no way to build a foundation for the pillars.
Surely it should be built with blocks down to the bottom of the tank before it was backfilled.

I believe you can't use blocks for grant job, but I know what you're saying

valtra2

You have to build pillars all the way from the bace of the tank up no matter what backfill. Builder should have known but if not on plans then like last poster said it's up to you. We always build dry blocks up as pillar and backfill with care

valtra2

larrymiller wrote: »

I believe you can't use blocks for grant job, but I know what you're saying

Yes you can.

larrymiller

Reggie. wrote: »

That would be the builders fault so. Imagine if the shed was half built

If it was half built I would be in some mess

larrymiller

valtra2 wrote: »

Yes you can.

I think it changed recently. I'll post a screen shot if I can find it

valtra2

larrymiller wrote: »

I think it changed recently. I'll post a screen shot if I can find it

Ah maybe it's a few months since we last done one

screcrow

Can you rawbolt the pillars to the back wall of the tank and then pour concrete around them up to the height of the slat with some rebar if it's on the open side of the shed
If it's for the back wall you have a bigger problem you need foundation for that wall
too late now but you should have put a 15 inch wall on the back of the tank which will give you lots of room to take the wall up another 8-ft and just use piller stumps at the top

larrymiller

TBH I've no experiance with building hence getting a contractor in.

Anyway he's coming to look at it and will fix it this week.

grassroot1

How long was it back filled.Probably settled with all the rain I did a pad here for the pillars but we went full lenght of the tank and put steel mesh in it.

Wildsurfer

screcrow wrote: »

Can you rawbolt the pillars to the back wall of the tank and then pour concrete around them up to the height of the slat with some rebar if it's on the open side of the shed
If it's for the back wall you have a bigger problem you need foundation for that wall
too late now but you should have put a 15 inch wall on the back of the tank which will give you lots of room to take the wall up another 8-ft and just use piller stumps at the top

Pour a full 15 inch wall just to take a few pillars... not very cost effective. Dry building with blocks underneath pillars as already suggested is the correct approach. You would have to question credentials of builder who poured those pads. Op got lucky rain came when it did.

foxy farmer

I was working a day job back in 95. Was young and green to building. Got a highly recommended contractor in to do a slatted house. Pulled a similar trick. Dug down threw in a few blocks as a base stood rsjs and concrete around them. 23 yrs later they're still sinking. Just one of several problems.
That photo has alarm bells ringing for me.
I suggest you get out a good long measuring tape and measure everything before meeting builder just in case there are other issues.
A stub wall down to the tank foundation and tied to the tank wall is the only job for carrying shed rails in your situation.

Cavanjack

larrymiller wrote: »

I think it changed recently. I'll post a screen shot if I can find it

I read the specs a couple of weeks ago, just said to have a solid base to the foundation afair

patsy_mccabe

I always wondered how they put in these pillar foundations. Seen loads of pics of back filled tanks and wondered, where are they going to put the pillar foundations.
As foxy farmer said above - "A stub wall down to the tank foundation and tied to the tank wall is the only job for carrying shed rails in your situation."

cute geoge

That was some mickey mouse attempt at base for poles!!!!
I remember before backfill we used fill a oil barrel with conco and have another oil barrel on top and put the rsj in this

valtra2

patsy_mccabe wrote: »

I always wondered how they put in these pillar foundations. Seen loads of pics of back filled tanks and wondered, where are they going to put the pillar
foundations.

It's the same as all foundations you have to get down to original solid ground.

Sacrolyte

valtra2 wrote: »

It's the same as all foundations you have to get down to original solid ground.

+1000

Snowfire

https://youtu.be/rUHunfH0XbI

BorneTobyWilde

Just looks like a blob of concrete in a hole of soil, wtf.

screcrow

Wildsurfer wrote: »

Pour a full 15 inch wall just to take a few pillars... not very cost effective. Dry building with blocks underneath pillars as already suggested is the correct approach. You would have to question credentials of builder who poured those pads. Op got lucky rain came when it did.

You'd be surprised how cost-efficient it actually is especially if you have to buy good quality backfill which you should use against a 9-inch wall in a 60 foot wall it's only another extra 6 square metres to go from 9 inches to 15 with a 15 inch wall you can throw whatever you like against it .works out far cheaper if you have to put a back wall on top of it instead of good quality filling and foundations for that wall and you don't need to put in shed pillars all the way under the floor stumps on top of the wall will be perfectly adequate

I would run whoever poured them pads as they don't look deep enough for starters that is an absolute disgrace of a job also wondering why the slats come out to the very top of the wall usually only come out about 4 to 6 inches

Who2

Chemical anchor in rebar into the tank and bent down into the pads then pour all around it, including existing pads. Get it poke red down the sides and it’ll never move. Unless you’ve a clear span shed of 60ft or more I can’t see it going anywhere. You are where, you are it’s unfortunate but there are ways of fixing it.

Good loser

Who2 wrote: »

Chemical anchor in rebar into the tank and bent down into the pads then pour all around it, including existing pads. Get it poke red down the sides and it’ll never move. Unless you’ve a clear span shed of 60ft or more I can’t see it going anywhere. You are where, you are it’s unfortunate but there are ways of fixing it.

Sounds a good enough solution to me.


You mean drill holes into the concrete pad and the silo wall? How many holes per pad and what size rebar?

screcrow

Who2 wrote: »

Chemical anchor in rebar into the tank and bent down into the pads then pour all around it, including existing pads. Get it poke red down the sides and it’ll never move. Unless you’ve a clear span shed of 60ft or more I can’t see it going anywhere. You are where, you are it’s unfortunate but there are ways of fixing it.

I would still be inclined to rawbolt the pillars into the tank wall it makes them very secure no matter how bad ground but would also do what you're saying and chemically anchor the concrete around them especially ground is bad and shed is big

White Clover

Barrels as cute geoge says is the best job. Give him a good bollicking for putting that stuff in as "backfill" . It's the furthest thing from it.

Cavanjack

Good loser wrote: »

Sounds a good enough solution to me.


You mean drill holes into the concrete pad and the silo wall? How many holes per pad and what size rebar?

Is this a grant job?

Odelay

Who2 wrote: »

Chemical anchor in rebar into the tank and bent down into the pads then pour all around it, including existing pads. Get it poke red down the sides and it’ll never move. Unless you’ve a clear span shed of 60ft or more I can’t see it going anywhere. You are where, you are it’s unfortunate but there are ways of fixing it.

I wouldn't let him stick anything structural off the tank. He can go back and dog down to solid earth and build up from there as should have been done first time.
If you agree to a workaround that "should" work, you'll be left carrying the can if something goes wrong in the future.

Wildsurfer

screcrow wrote: »

I would still be inclined to rawbolt the pillars into the tank wall it makes them very secure no matter how bad ground but would also do what you're saying and chemically anchor the concrete around them especially ground is bad and shed is big

Usually you would be leaving a foot or two of a concrete apron at back of slats though, so pillars would be too close to slats if attached to wall, and also very doubtful that tank was built 100% straight so if pillars are rawl bolted to it they might be off line.

larrymiller

He came and apologised. Digger coming Tuesday. He will dig down to the base and build it up. Covering all costs.

Snowfire

larrymiller wrote: »

He came and apologised. Digger coming Tuesday. He will dig down to the base and build it up. Covering all costs.

That’s exactly the right way to do it, it’s going to be awkward to dig down without putting pressure on the walls of the tank tho.

Say my name

larrymiller wrote: »

He came and apologised. Digger coming Tuesday. He will dig down to the base and build it up. Covering all costs.

It's amazing that you had to educate him on how it should be done.

patsy_mccabe

Why don't they step out the outer shuttering to make the bases for the pillars. Pour it all then in one go. Strongest option of all.

screcrow

Wildsurfer wrote: »

Usually you would be leaving a foot or two of a concrete apron at back of slats though, so pillars would be too close to slats if attached to wall, and also very doubtful that tank was built 100% straight so if pillars are rawl bolted to it they might be off line.

Good point wildsurfer it needs to be pretty straight and square but I would prefer to have the apron at the front rather than the back has the front ones stay a lot cleaner where there eating

QHopefully he will come and fix it I presume that's the front of the shed and they won't be putting a wall there or I would be making him put in a full hardcore backfill

the_pen_turner

patsy_mccabe wrote: »

Why don't they step out the outer shuttering to make the bases for the pillars. Pour it all then in one go. Strongest option of all.

because that would be a huge amount of extra work

Trasna1

larrymiller wrote: »

He came and apologised. Digger coming Tuesday. He will dig down to the base and build it up. Covering all costs.

Building up with what? Block stub wall? Lean mix?

screcrow

patsy_mccabe wrote: »

Why don't they step out the outer shuttering to make the bases for the pillars. Pour it all then in one go. Strongest option of all.

had to get the shutters to stop in the right places that you can put corners and turn in and out and remember you need to put the pillars into this concrete which would be nearly impossible shuttering is wavy enough without a 20ft pillar sticking out of it

Muckit

Did all of the stands for shed uprights myself for our own slatted shed when twas built 20 years ago. Shed is still standing! Theres more than 1 way to skin a cat but this,is how l did it.

I was 20 at the time and had no building experience. I didnt even do construction in sec school! I hired an electric mixer and built up pillars using 4 and 6" blocks laid on the flat. 2 blocks, then next row going opposite way. Spirit level to check plumb. Finished with a small square bale of hay standing up and the digger lad back filled.

Another thing l did was cut off all the shuttering ties and put a dab of mortar to cover the steel! Then rolled the whole inside surface with a waterproofer.

Twas a small shed but a lot of work now that l think of it for one young lad on his own.

Dakota Dan

larrymiller wrote: »

If it was half built I would be in some mess

You'd have a very low shed.

memorystick

6 inch down from the lowest point I dug to the foundations of the pillars. The cheap job is the dear job.

valtra2

Who supplied the backfill material