Plumbing / Flooring (O/T - Apologies)

[The Great Fandango]

Hi Guys,

Sorry for the obscure question...

12 months ago I had the whole of my central heating piping re-routed.

My obsessive nature wanted all pipes under the floor instead of trailing down the walls.

The trouble (for the plumber) was the ground floor of my house is asphalt. Three weeks and 2 tonnes of dust later the job was done.

The pipes were all covered in thin lagging and buried in channels approx 2 inches deep. A layer of concrete was placed over the top.

...

With my restricted cash flow, I never got round to putting the wood/laminate floor down over the top of the whole mess.

I'm glad I didn't because I can see now that the concrete is simply crumbling with the heat (and people occasionally walking on it).

My question is this...

What would people recommend as an alternative to concrete for permanently bury the piping? Preferably more resilient to stepping on and the warmth from the pipes. I've heard there's a good (but expensive) self-levelling acrylic which sets rock hard?

As always, your help is much appreciated.

Best regards

Kyle, Leeds

[Man On The Clapham Omnibus]

My twenty year old kitchen extension has a solid concrete floor and the pipes go under that but not in lagging. I laid 1" bore high density polythene tubing and threaded the copper through that to give a decent airpace around the copper. It allows for movement freely and only bare feet or a cat can feel the warmth through the concrete.

[carpetstu]

I recently carpeted a new barn conversion. The owner / builder, like your self wanted the pipes below surface but also accessible in a concrete floor.

He simply made a channel and put support struts along the length 6mm below surface then topped with 6mm ply board.

No problems with expansion... no problems with access to pipes etc and he could fill with laggging to insulate and protect the pipes.

[Bean]

I ran polypropylene central heating pipes in my spare room, under concrete floor.

I dug out a channel six inches deep or so, filled with sand level to the pipes then put a couple of inches of fast setting concrete on top.

[a4gom]

In my old house I managed to get most of mine behing the skirting (up to 4" of plaster on the walls in some places it was a very old house) but had to cross the entrance hall under the floor. My floor was asphalt too, I did as you have done and my concrete cracked too, in the time I lived there we had two carpets and laminate in that area and I had no probs with the cracked concrete. It can't go anywhere can it?

[brianm]

A bit confused when you say the surface is breaking up as I would have thought the pipe routes would be buried around the edges and immediately next to the theshholds, ie under the cill, to avoid this degradation?

These are looked on as low traffic and even if clad over should give little problem?

[gp350se]

Hi Kyle

If its crumbling it sounds like the mix might have been wrong as sand and cement usually set very hard and heat doesn't effect it.

[perksy]

Hi Kyle

If its crumbling it sounds like the mix might have been wrong as sand and cement usually set very hard and heat doesn't effect it.

Have seen this happen before on a few floors that have been patched where the mix has been wrong

Tapped one with a hammer and it crumbled like a cadburys flake    

[tex]

you can buy a product which the name escapes me - its a concrete mix but its like water - mix it pour it down it levels the floor and finds its own level - (use shuttering) good stuff - had similar probs years back with old house where concrete was crumbling cos basically the numb nut who laid it must of used wrong mix.. easier to lay this stuff on top - set rock hard - smooth and level.. great stuff was impressed - think B n Q sell it..

[ACW]

I'd have put Ply covers on so that you can access it later, but rake out the concrete and since it will only be a smallish volume, get hold of B=Q own brand self levelling floor screed. add water, stir, pour. leave it a couple of days to set fully (pref with pipes cold) job done.

Your mix was probably too thin on concrete, had wrong amount of water, or far too much traffic in high heels

done this recently. for 2" depth you might need to lay in a couple of goes, as such a depth will tend to slump a little as it dries.

http://www.diy.com/diy....ch=true

[carpetstu]

STOP>

The B & Q one is absolutely S**T, and I wouldn't use it in any circumstance.

Although it's a latex screed its water based. You would be best using a latex 2 part screed. These come with a bag of self level compound and a bottle of latex milk which is mixed on a one to one basis. As its true latex it will expand and contract as needed.

Before this is applied you still need to remove any lose concrete and fill, best to use something like Ardex rapid.

With the type of sub floor, you have, it will need a primer before screeding, use F.Ball p131.

Do not do any of the above if there is damp in the floor.

Remember self levelling will raise the height of the area this may cause issues where it meets other levels.

You will not get this lot from a building merchant, you will need a good flooring supplier.

Edited to add - let me know if you want a supplier, I will have a word with the rep's and locate one in your area.

[Mark Stanton]

If you want some good quality screeds and concrete repair systems then check out Fosroc         available at all good builders merchants (and some bad ones)          

Fosroc are based near Tamworth next door to Drayton Manor Amusement Park       and supply direct to trade only  

[conibear]

Can't advise on concrete but I can regarding the pipes and floor laying.

Your LPHW system could be circulating at 80C, which would have an effect on whatever man made wood based flooring you propose to lay. Insulate throughout (vapour sealed) the pipes with 13mm if you can, otherwise 9mm should be ok. As a second protection to your proposed floor, lay on top of the insulated LPHW pipes (wider than the pipes area), thin tin 20 gauge or below, this would deflect the heat that may pass through the insulation and prevent your wooden based flooring from delaminating.

Most if not all, man made woods and laminates would start to seperate at 45C, as the adhesion melts basically.

That would include any laminate floor, ply, MDF etc..  

 

[The Great Fandango]

Thanks for all the suggestions and advice... wish I had a photo to post on the thread to show you the situation so far.

The plumber may well have used the wrong 'mix'... Indeed it crumbles when you put a hammer to it.

With regards to the flooring, I'm going to most likely go down the reclaimed timber 'proper' wood floor. The heat from the pipes baring comes up through the concrete (enough for the cats to sleep on it I guess) but I had plannd to simply lay kitchen foil down to stop the wood from getting too warm.

CarpetStu, I'll message you regarding those products and getting them in the Leeds area.

Thanks one and all.

PS: I HATE SPENDING MONEY ON THE HOUSE!... That's valuable car upgrade money!

[wacomuk]

expanding foam!!!!!! it fixes everything !!!!!!!!