Floor Slab - Poor Quality Job ?

[paulandfrodo]

Morning,

I would appreciate some comments / feedback in relation to a slab that has been poured by a subcontractor. I've prepared the area with blinding/dpm mesh & concrete mesh men. It's a pour of 130m2 and it was to big for me to do on my own.

Contractor was employed to supply men/concrete and lasers/tapping equipment.

I feel the guy has totally screwed up and left me in a bit of a hole. It is a hole I can get out of but it's just adding expense and complications to an already tough project.

Three gems of info from him on the day...

1. Mid way through he asked where my datum point was
2. He changed his estimate from +-5mm to +-5mm either side of the laser - so 10mm
3. Upon leaving he told me he's seen much worse jobs

Unfortunately I am not a 'concrete expert', so on the day, I kept out of the way and let him do his job. And only the next day could I get on and get a 'feel' for what he did.

Now, the last slab I did (and I do them rarely) it was 40m2 and I was +- 2mm and we laid a laminate floor (with 3mm foam roll) straight ontop.

I've surveyed the floor with 120 odd points and at worst he's -34mm off what is the highest point on the slab.

My problem is we need to put stud work on this. The floor is also taking 75mm insulation, UFH & then a 50mm poured screed and it's just going to be a pain to work with. It's all solvable, it just time, money and head work.

at +-5mm the above work is totally viable.

I've attached the readings I've taken from the floor.

 

[dazlight]

I don't do sub floors myself but go over a lot of bad ones.
Some builders say they can do it and ain't got a clue.
I end up using lots of smoothing compound to sort it out and costing a lot of money

 

[paulandfrodo]

The area is being split into smaller areas. After this is done, I will then mark out low/high points and use a runny mix of self level to take out the worst. This will allow no hollows to be under where the PIR goes, so when the 50mm screed goes down it should sort out the problems.

Their is always a way to solve problems. I just didn't want them in the first place. I should have gone with my gut on this crew.

The last slab I did was 7.5m x 4.8m. I was +- 2mm, but I did take my time. You can now see why I was so annoyed with these guys.

They have not been paid anything yet fortunately.

 

[vinn]

Its common with a pour of that size for a section dwg. to be given to the concrete contractor. Datum(s) & penetrations would be noted.
Plus all subs should be walked through the job before any work commences.

 

[paulandfrodo]

Vinn,

In hindsight that makes complete sense. I wasn't however asked for any such details. If I had, I would have happily given them. Esp. as Datum's had been extended to other parts of the building and were still (and still are) in place to allow me to understand levels throughout the entire build.

Paul.

 

[paulandfrodo]

I had given the contractor my SE's drawings in relation to the slab construct.

Had seen the site three times, so he knew the area he was dealing with.

And looking at my emails, I can see explicitly asking him to ensure he had lasers and app. equipment to ensure the slab is "all at the same height".

 

[paulandfrodo]

dazlight,

Can I ask what compound you use, or were you using a generic term for essentially self - levelling compound ?

After the rooms have been split up into more manageable sizes, we will go round with a level highlighting low/high points to determine where we need to fill. We essentially want to take out hollows so the celotex/ecotherm has less of a hollow underneath, thus attempting to minimise the possibility of movement/settlement.

Then we will use 75mm PIR, then UFH pipes and then a liquid screed. I need to chat to the liquid screed people to determine how much the weight of their product will help deflect the PIR and equally how much the UFH pipes will attempt to keep the PIR in place and counteract the weight of the screed.

 

[dazlight]

I see 1 in 10 good screeds. Watched some lads pour it in and just trowel it. No lasers or chalk lines.

Wrote that yesterday but didn't post ?

Yes Paul. We use a lot of Uzin products now.
But depends what you can get.

Some good fibre screeds out there like TA level flex.

The best ones are by

Uzin , F ball amd Ardex IMO

I turn up and check floor out with a with a level And my laser.
Then do pencil or chalk areas where to build up levels.
Then prime and screed them over a couple of days if needed.

 

[paulandfrodo]

dazlight,

Thanks for those product recommendations. They all look great for products to then lay a final floor on. I've used Uzin & Ardex before when then putting final floor finishes on.

In this situation where we are attempting to get a rough unlevel floor out to give me say a 5 mm tolerance before putting Celotex, then UFH then a pour screed. I will prob. go for something that is a tad cheaper, but essentially fills the holes.

I will prob. add a little more water than normal to allow it to flow a little better as no matter what 'self levelling' compounds I've used they all seem to need a little bit of a trowling to assist their movement.

Equally, a little extra setting time (due to wetness) is fine as we've got heaps of other things on the job we can do.

 

[dazlight]

Have you got a spike roller? That helps a lot

 

[paulandfrodo]

dazlight, nope! But I can get one. The lad who will prob. end up smoothing the stuff out is pretty old-school and will prob. do it with a plasters trowel and a lot of bending down. We can give one a go...

I presume you mean something like :-

http://www.theunderfloorheatingstor...gle_shopping&gclid=CPHNz4-N2cwCFQPgGwodr6IH5Q

 

[paulandfrodo]

And, of course, a bucket of water to dunk it in afterwards !

 

[dazlight]

That's it mate. You still trowel it but then run that over it to help smooth it out

 

[paulandfrodo]

Well, we are putting our base plates down and packering so level, so I can see how "out" the floor is. Some areas worse than others... Some REALLY bad !! Well, the contractor has not, as yet contacted me about payment !

 

[dazlight]

Any pics Paul