Hello

Am desperate for some advice from anyone out there - I have just had a new heating system installed and had the pipes laid into the floor (concrete) - the original sand/concrete screed cracked and crumbled, espcially in the hallway, so had the guys back, they were originally going to lay concrete over the top until I asked them to take out the crumbling stuff, the pipes looked to be laid into sand, not lagged - he then laid a stronger concrete mix, and guess what, this has started to crack and crumble - we had a general builder in who laid a self levelling compound over this and yes, you guessed it..... so my question is, should the pipes be lagged and what can I lay over them which won't crack/crumble, we were hoping to either lay laminate floor or tiles, or maybe lino which looks like laminate - hoping someone, somewhere can help as now don't know who to believe!? Alos had electric UFH in the bathroom laid, waited about 6 weeks to switch it on, and one of the tiles is now moving and the grouting crumbling around it - any suggestions, or is it a case of take the tile up and re-lay, will this damage the UFH?

Are these pipes feed pipes to radiators or under floor heating. Without know what materials were used its hard to say about the cracking other than it really shoould have been a flexible levelling compound.

as sir ramic says a bit more information needed please

as for the bathroom floor what was the substrate . i,e plywood floor, did they self level over ufh, what adhesive and grouts were used as it should all have been flexible, was the floor solid with out deflection

Thanks for replying - the pipes are leading to radiators, and the original filler looked the colour of wall plaster, which I thought it was, but they said it was a bad mix of concrete filler/ not their usual brand, the next lot was just standard concrete mix I believe, not flexible - should the pipes have been lagged at all, have read about copper pipes reacting with concrete/plaster?

The bathroom substrate was plywood, the floor boards were removed to gain some extra depth to allow for the underfloor heating/tiles etc, so it was newly laid, not whether they self levelled over UNFH as I wasn't ling there at the time, but going by time frame I doubt it, I saw the UFH one day and then the next they started tiling - is that bad?

They should have been lagged with something at least.

just wondering do you know how thick the ply was,, the right way is to self level over ufh with a flexible screed , this also protects the wires when laying the floor, if they just tiled over the wires , and some of the wires are not fully covered , they can burn out making the ufh useless , the grout crumbling away suggests they aint used a flexy grout or to much bounce in the floor

any pics off the floor in the hall way and bath floor

Hello

Sir Ramic - If the pipes are bedded in sand, would that work as a "lagging" and would I only have to worry if there was cement touching the pipes?

nybor62 - No pics of the hallway, as now been covered in a self levelling screed - should we remove it and start again do you think? then maybe I could get a picture of the pipes. The contractor who laid the bathroom UFH and tiles has said he will come back and take a look at the floor, he's a "sensitive type" who doesn't like being questioned, but what should I be asking him, how think is the ply? did he level over the UFH cables, anything else?

I have to confess that I am no plumber but I have never seen pipes without lagging in screed/concrete. usually all i get to see is the tell tale sign of lagging when the pipe work comes up through the substrate so I assume it is all lagged.

the ply should be 15mm minimum ( BS)
as for the self levelling, its not actually necessary but highly reccomended IMO

are they copper pipes Tinkerbelle, or plastic ones?

if they are copper, then they should be lagged in something to stop deterioration in the event that the copper and the concrete react with each other. if they are plastic pipes (usually blue if carrying water), then you may not need any lagging but it's worth checking with a plumber.

my parents had copper water pipes sunk into concrete in their extension and after 25 years a massive leak began just after Christmas and ruined the concrete floor in their kitchen and dining room. and because it wasn't due to weather conditions, it was not covered under the house insurance as accidental damage either, so my parents have carpets up all over the place waiting for the concrete to dry out.

how thick was the original sand and cement screed they put down , have they not been able to give you any answers as to why it keeps cracking, , im no plumber so cant really comment on the pipe work , but would have thought it should be lagged

The sand/cement screed was probably about 3 inches, not entirley sure, I just saw a brief flash when they were removing the crumbing bits, the cement replacement "top" was probably only 1/2 inch? The pipes are all cooper and all they've said is that they can assure us they will be fine, but not why it keeps cracking?

There's obviously movement, so when we walk on it, it moves and "snaps" am loathed the get them back, but maybe there's no other way?

Probably keeps cracking because of expansion and contraction of CH pipes. The pipes should have been installed inside a conduit. This would stop the pipes coming into direct contact with the screed and also stop the screed cracking from expansion/contraction.

As said copper pipes must lagged or covered to avoid contact with cement screed..how long was the screed left before the central heating was put on.

copper pipes and cement dont mix,they should be covered in pipe insulation and taped.......so my plumber tells me

At no point should copper pipes and cement come into contact.
As a very minimum, the pipes should have been covered/taped.
The above is to protect the pipes, and does not cover your other problem.

The problem with the cracking is due to heat expansion and/or a weak screed mix.
If i had to run copper below concrete/screed, i would run them through conduits.
I would leave enough room at each end to allow them to expand and contract.
However, i would use plastic (x-barrier) pipe if it was my choice.

Without seeing the work, and without knowing all the circumstances, i kind of get the impression you are being fobbed off.
They are trying to "band aid" a mistake, that will only be sorted by digging up the entire floor.
The pipes want re-running in conduit, or at very least covered/lagged. (this does allow a slight amount of movement)
My preference would be to swap the pipes for plastic (x-barrier) for the part that is below floor.
The floor should then be re-screeded.

Consider contacting your local building inspector.
Your council office should be able to give you his/her number.

The pipe should be wrapped in pipe wrap or hairfelt or similar when encased in a floor. I encase all pipes copper or other wise, the pipe can be grey or white for domestic. (The blue is incoming mains only)

If the heating is switched on when the back filling is still wet then it will shock it and crack and dry it too quickly. Not a great time of year to do it unfortunately

Cement corrodes copper over a period of time copper pipes must always be lagged when in screed the problem is no lagging which also allows for expantsion and the pipes are not laid deep enough in the screed .To do the job properly the pipes need to be relayed in a deeper channel and some form of lagging put round them ,just putting new bit of screed over pipes how ever strong will not work.Its a bigger job than they want to let on