Screed on top of screed advice please

[daveandkells]

We have recently had an new extension built on to the side of our house, the extension is approx 7m x 3m, however when the builder screeded the floor across the side extension it runs out by 55mm over a 3m width.

He proposes to cut it back to give a 25cm to a 55mm additional coating of screed to level it.

We are laying an Amtico floor on the finished screed and the flooring company recommend the whole floor to come up and re laid level as laying Screed on top of screed can not be guaranteed not to break up in the future especially going from a depth of 25mm.

Does anybody have any advice please ?

 

[Shytalkz]

Yes. It won't work. The thin stuff will curl and delaminate from the original screed and it will soon break up. The flooring company are 100% correct.

 

[daveandkells]

Yes. It won't work. The thin stuff will curl and delaminate from the original screed and it will soon break up. The flooring company are 100% correct.

Thanks for that you have confirmed our fears, do you know of any standards or anything we can suggest our builder refers to to back up our cliams.

He insists we are to complanciant, but we think he is trying to pull the wool over our eyes.

Unfortunately when the floor breaks up he will be long gone and we will have to pick up the bill for the repair works !!

 

[Shytalkz]

Makes you wonder what else he's bodged on the job...

Abso minimum of cement/sand screed is 38mm - and that needs chicken mesh in it to even stand a chance of not cracking up, debonding or curling.

There are specialist screeds (example) that might go a bit thinner, but then they normally need very careful prep of the substrate - and I can't imagine for one minute that any specialist company would guarantee it sat on top of another screed of unknown quality.

He's ferked up, he's trying to wriggle out of it by doing a bodge job, don't let him.

 

[JerryM]

any standards or anything we can suggest our builder refers to to back up our claims

this is not an easy one and probably why so many disasters happen.

i guess the work must be with building control and u could ring them to get their input (or in the 1st instance suggest to the builder this approach if he's not for going along with the revised approach).

alternatively a trip to the library for the relevant BS (or EN these days). BS8204 i think is the most likely. and for me this is where the difficulty is. they always seem to be very theoretically based and don't take onboard on the job learning.

they also cost a fortune - hence the long trip to the library for some and ignorant bliss for most

 

[Shytalkz]

I'll look the BS up when I'm back in the office on Monday and let you know.

I doubt that building control will be that interested, tbh. If you'd got your electrical sockets 50mm too low on the other hand...

 

[Balenza]

daveandkells wrote

side extension it runs out by 55mm over a 3m width

Does your builder use a level ?.
I expect not.

He proposes to cut it back to give a 25cm to a 55mm additional coating of screed to level it.

Do you understand what he is on about because I don't understand what you are on about if what you have written is about what he is on about.
Can you clarify ?.

Cut it back
????????

An additional coating of what you are suggesting above will not leave the floor level if it is out by the amount of 55mm over 3m.

Does anybody have any advice please ?

Yes. Get a decent jack hammer and remove the lot and then introduce your builder to a piece of equipment called a LEVEL.