Concretely Buggered! :(

[Barney12]

So today was the day that we were pouring the slab for the garden room (8x5m) but a perfect storm approached. I was called away early this morning due to a work commitment so wasn't there to assist as planned. As a result I had to leave the groundworker (a top guy I've used a lot) and a hired hand. Combine that with a blisteringly hot day and it all went wrong

I came back tonight to the groundworker sat on the floor with his head in his hands and clearly devastated by the result. I genuinely felt sorry for him. 

 

These were hourly rate guys working to my spec and materials so this one is my cost and now just need to work out what next? The slab had rebar mesh so should still be reasonably sound. 

 

A few options as I can see it but would welcome the collective thoughts?

 

1. Screed the slab

2. joist and timber deck floor (A chance to add a bit more insulation?)

3. Add to the shuttering and pour again after a liberal dose of SBR

 

Here's the photo's in all their gory detail. 

 

 

OH BOTHER  

 

[Miek]

What's your desired floor finish? It's a garden room so thinking maybe waterproof? 

 

If not you could batten the floor with packers to get a level, then board it. 

[Miek]

Hire a strike roller next time

 

[Barney12]

3 minutes ago, Miek said:

What's your desired floor finish? It's a garden room so thinking maybe waterproof? 

 

If not you could batten the floor with packers to get a level, then board it. 

 

A little undecided. Its actually going to be a gym so possibly a hard wearing laminate. Alternative would be tiles but thats a bit cold. 

 

[Simplysimon]

i'm presuming it was a mixer, a shovel and barrows as if it was by jigger then it shouldn't have ended up like that? even if it was surely they could have run a straight edge over it as they went waiting for the next mix to be ready?

[Barney12]

3 minutes ago, Simplysimon said:

i'm presuming it was a mixer, a shovel and barrows as if it was by jigger then it shouldn't have ended up like that? even if it was surely they could have run a straight edge over it as they went waiting for the next mix to be ready?

 

Nope it was a 6 cube premix load. I really don't know what they did as I wasn't here and if I had grilled the poor chap tonight I think he would have burst into tears  

 

All I do know is that they definitely had a straight edge but it was going off faster than they could level it.

Edited May 22, 2019 by Barney12

[Olly P]

Same happened to me with my garage. We got hold of some industrial self smoothing screed that we mixed and applied then painted and its had some hammer over the last 10 years or more and is still as good as when we did it. 

[Simplysimon]

1 minute ago, Barney12 said:

 

Nope it was a 6 cube premix load. I really don't know what they did as I wasn't here and if I had grilled the poor chap tonight I think he would have burst into tears  

i would definately have got the bbq out and some marinade

[Declan52]

It's just dried out to quick in the sun. Should have put a hose on it as it went in keeping a mist on it.

Hack of any lumps and a few bags of self leveling and no body will be any the wiser.

[Temp]

Two blokes should have been ok with that. Wife and I did a 6m x 5m 150mm thick slab on our own but I had a dumper to drive the premix concrete around the house. Hardest part was working a beam back and forth across the top of the shuttering to get it level.  I'm wondering if you didn't have quite enough delivered? If you end up a wisker short it's much harder to level because it's below the top of the shuttering.

 

I think I would take deliver of the building and measure it to check exact footprint. Then build a 1 course brick wall with DPC on top (around the edge to raise the building and stop any water running in under. Sweep and sand blind the concrete. Lay DPM, insulation and boards on top.

 

 

[Triassic]

Let’s look at getting the problem sorted. I’ve had a similar thing happen to me on a previous job. I laid a slate tile floor over the ‘problem’. We simple used a dryish biscuit mix, with the slate tiles laid onto the mix before it went off. The tiler guaranteed the job and none of the slates ever moved.

[Mr Punter]

Get a powerful jetwash to clean all the laitance and loose material.

 

I am not sure where your DPM and insulation is going.  You could just have a screed to level it, some insulation and 22mm chipboard floating floor.  If you have tiles in the room they may get broken with weights / equipment, so vinyl would be better.

[Ferdinand]

Agree, clean it down and see what you have.

 

If it is just a gym, then consider rubber matting directly onto the concrete. Either the rubbery chopped strand or spongy stuff, or real gym mats, between say 10mm and 20mm. It would be between about £5 and £20 per sqm if you buy carefully.

 

18mm ply is OK as an insert for free weights.

 

Suspect you may want a less specialised surface, however ?

 

Ferdinand

 

Edited May 23, 2019 by Ferdinand

[Bitpipe]

Sound advice above.

 

Can I just say well done for keeping your cool and not giving the trades person a roasting, which would be the default approach for many I think.

 

 

[Construction Channel]

It may have gone too far as its been pretty hot here today but I would get a scraper (batten on a stick if you have to) and try to knock off most of those stones sticking up. It will be much easier while it's still green. Also much cheaper to fill the holes they leave than bring the rest of it up to their level. 

 

Concreting in direct hot sun isn't fun. Your constantly chasing it.  those that said. "they should have" /"I would have" /"why didn't they". Have clearly never had a concrete pour get away from them. When it happens there really isn't much you can do.

Fwiw it looks fairly true to the shuttering just a bit rough on the surface. Think of it as a good key for the latex to stick to. ?

[Barney12]

Thanks for the replies.

 

Caught up with the guys today and they really did get caught in a sh*t storm. 

The cement had to be dumpered 100m to the pad which they did quickly to reduce waiting time but then the track came off the 8T digger. They were forced to push a 8 cube pile by hand with one man trying to get the track back on. As @Construction Channel said it simply got away from them, nobody’s fault and nobody died. 

Im not one for shouting and screaming or blaming. Self buildings hard enough without falling out with people that have worked bloody hard for me over time. 

 

As as for the solution well we’re going to add a concrete screed cap. 

 

 

 

Edited May 23, 2019 by Barney12
Typo

[CC45]

22 hours ago, Declan52 said:

Hack of any lumps and a few bags of self leveling and no body will be any the wiser.

as above.  Job sorted.

[Nickfromwales]

3 hours ago, Barney12 said:

Thanks for the replies.

 

Caught up with the guys today and they really did get caught in a sh*t storm. 

The cement had to be dumpered 100m to the pad which they did quickly to reduce waiting time but then the track came off the 8T digger. They were forced to push a 8 cube pile by hand with one man trying to get the track back on. As @Construction Channel said it simply got away from them, nobody’s fault and nobody died. 

Im not one for shouting and screaming or blaming. Self buildings hard enough without falling out with people that have worked bloody hard for me over time. 

 

As as for the solution well we’re going to add a concrete screed cap. 

 

 

 

2-part leveller like we chucked on your floor will suffice.  Really no need to go for a full concrete screed cap, as that'll need to be at least 30mm to stay stable. SLC will be kinder too, with no need to level it manually.  . More chance of that breaking up vs SLC.

Reconsider !

[Temp]

Do you want to use it in winter?

[Barney12]

So to update my thread. In the end we added a 50mm concrete cap. A good dose of SBR before it was laid. As we need a few cube of mix for another area it just worked out the cheapest.(and quickest) fix. 

 

The oak oak steps are also now in place which will lead down to the garden room.