Latex floor question and floor levels problem :(

[shd1970]

Hi there,

I have had a new 4.5m x 4.8m extension on the back of my house.
The old outside wall is now gone leaving us with a lovely open plan living/dining room....we are really happy with it so far.

But........
The floor levels are hugely different....over 20 mm between where the old and new floors meet at one point...perhaps a little more !

The new floor was a "latex screed" that my builder raved about.
"rock hard"...."dries harder than concrete !" he said....who was i to argue !!!

The screed was a white milkshake type consistency laid by a 3rd party and was approx 2-3 inches deep i would guess...perhaps more / perhaps less. He was chuffed to use it as he openly admitted that it saved him a stack of time putting a traditional concrete screed down.

This was poured (and then jiggled around with a long metal contraption !) onto a concrete base with reinforcement.

So questions....

1 - Latex screed.....are they any good / will it last ?
2 - What should i expect my builder to do to correct the floor level ?
He knows we planned a wood floor and speaking to an expert wood floor company, their preperation would be as there is a BS standard is that over a 2 metre span, the acceptable difference is the thickness of a £1 coin !

Should he / would he need to PVA it and then use a levelling compound ?
Is a levelling compound ok to be that sort of depth ??

I'm not unreasonable or was i perhaps expecting a little too much for the floor levels to be a lot better than that. I'm just disappointed that having to put something else on top just seems a little bit poor.

I know the carpenter who is to put the floor down was shocked.

Thanks in advance to anyone who has the time to shed some light on the latex screed and how best to sort the levels.

Thanks in advance.

 

[SKETCH3D]

I had to level up a floor in my conservatory as the builder we bought the house from did an awful job of laying the concrete. However this was only to a depth of around 10mm falling to one corner.

I don't think leveling screeds are suitable for 2-3 inches, but you really need to read the manufacturers data, the product your builder used may have been suitable. Otherwise latex screeds are great to level up small inconsistencies.

When leveling up my floor, I did still get a ridge where the leveling screed finished and I didn't get back to it quick enough to feather out the edge. I was able to hide this as I put insulation over this then a chipboard floor before I put my finished floor down, but I doubt you have that luxury.

A builder I spoke to prior to doing the job did suggest that I put diluted PVA over the existing concrete first.

 

[mointainwalker]

He was chuffed to use it as he openly admitted that it saved him a stack of time putting a traditional concrete screed down.

Well, I rather think you now need him to either tear it up or get him to lay a self-levelling compound at his - or his sub contractor's - expense. Don't let him attempt to use a mortar screed which will be much cheaper as it won't last being only 20 mm thick at its deepest point.

I think you should arm yourself with something in writing stating the BS tolerance as it is likely that he will try to talk about allowable tolerances to excuse this failure.

Some compounds will do up to 20 mm. I needed one recently and found a product made by Sika, but it was very expensive - about GBP 30 for a 25 kg sack or GBP 42 with fibre re-inforcement ! Sika products are generally expensive but even if you find something cheaper, this job is likely to cost hundreds of pounds just in materials.

You need to know what the first screed consists of, as some screeds ( anhydride ) contain calcium sulphate which reacts with cement-based prouducts and therefore needs to be primed before over-laying.

If you want to read about self-levelling compounds, then read this .
//www.diynot.com/forums/viewtopic.php?t=80333

 

[SKETCH3D]

Could have used that little nugget of information myself about a year ago. Instead had to spend hours on Google looking for information in screeds.

 

[shd1970]

thanks again for the input guys....really appreciated !

I have been doing some digging and i think the BS8201 (i think !) states that +/- 3mm over a 3 metre span is what we are talking.

Mind you, it looks like you have to pay to get a copy....what on earth !!!!
Surely these standards should be made readily available to protect consumers.

I have emailed the BS....no reply yet...........

I think its time for a chat with my builder.............

 

[mointainwalker]

Not sure if it's still the case, but larger libraries used to keep copies of British Standards.

BSI was made self-financing long ago, so they have to sell their services and products.

Let us know how you get on with builder. Of course, if you haven't paid him yet, you're well in .

 

[Monkeh]

Many libraries keep copies of the more common standards. With most libraries you can get online access to the bulk of them.

Let's see, BS8201:1987 says..

6.4.2 Surface finish and levels. <snip>

Localized variations in floor level should not exceed ± 3 mm from the mean when measured over a 3m distance using a straight edge.

 

[shd1970]

Cheers for to confirmation Monkeh !

+- 3mm over 3m...............


crikey.....do you reckon they would stretch to 30mm ?