Digging up parquet and concrete for central heating pipes?

Hello all,
anyone had any experience renewing all or part of a central heating system with pipes buried in the concrete floor of a 1960s (bungalow) building with parquet floor?
As part of our extension plans we will really need to renew the central heating. The radiators are rubbish anyway. I'm trying to minimise the amount of work needed on walls and floors in rooms not directly associated with the extension but with buried pipes there simply has to be some digging up.
I'd just be interested hear of any horrible experiences of doing something similar. Did you fill the entire universe with dust? Was it easy to get the parquet relaid well? Was it all worth it?
Before anyone asks: no, we won't put up with vertical pipes dropping down (whether boxed in or not) willy-nilly around the house. There are a couple of places where the drops can be placed sensibly and out of the way (cloakroom, and behind the dining room door, for example), but still a small area of floor in the hall and corners of the living room would need to be lifted to lay new pipes to get to the radiator positions and the the drops.
Michael
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Michael Kilpatrick coughed up some electrons that declared:

Would that be "real" parquet - or the 1/4" stick on tiles?
Do you want to reuse the tiles?
The latter can be got up gracefully (mostly) with a sharp bolster chisel, preferably in an SDS drill - if you're lucky, they pop off without damage, having just stripped some.
If you don't want to reuse the tiles, then a sharp spade knocks them off quite quickly.
I don't know about "real" parquet - as in thick blocks bedded on pitch - that might be interesting, especially as you'll probably want to save them for reuse.
If your floor is precious, I think you might find it easier to chase the walls and bury the pipes in the wall - it's not so bad if you use 10mm or even 8mm pipe for the drops, even if it goes to 15mm or 22mm in the ceiling - a wall chaser with a vacuum attached isn't too bad on a good day.
As to the concrete under the floor - you are either going to have to break it out (kango time), and damage your dampm proof membrane if you have one, then make it good or cut out slots with a disc then chase: the latter will fill the known galaxy with dust.
Let us have some more details and there might be some better answers :)
Cheers
Tim
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Tim S wrote:

It's "real" as far as I can see, and there is a thin layer of pitch beneath it. There are a couple around the edge of the living room that are damaged and no longer adhering to the pitch. Someone placed a carpet over the top of it some years ago and we removed it only last year. The morons just banged the carpet edging skipe-strip into the parquet and also stapled the carpet underlay, so I had to remove carefully the staples and nails.

The parquet is a typical herring bone pattern but around the edges has two runs of square-on blocks. It seems to me that it might be possible to attack the floor after only removing the two runs of edging blocks without harming the integrity of the herring bone (assuming most of the blocks near the edge are still stuck to the pitch).
The hallway is a T shape. Fortunately, across the junction of the "T" is exactly where some new pipes could be layed and again at this point there is a double run of square-on blocks that separate the herring bone areas of the two sections of the hallway - so again it may be possible only to dig up those blocks, not the herring bone.
I suspect repairing and re-laying the parquet is not the biggest issue.

well, surely the existing pipes aren't *too* close to the membrane, are they?

Michael
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Michael Kilpatrick coughed up some electrons that declared:

Ah - that's what I understand by "real"...

There's always one :(

I just wonder how hard it will be to unstick the blocks.

Relaying should be easy - it's the getting it up undamaged that may be hard.

Believe me - having watched builders on my floor, it is possible to cause widespread damage kangoing up concrete.
However... If your floor is like mine (1950's bungalow), you may have 4" concrete and 1-2" of screed on top (screed is normal, but there are no guarantees with these things). There will most likely be either be no DPM, a DPM sheet under the concrete or a bitumin type DPM painted on the concrete under the screed.
*If* you can bury the pipes in whatever depth of screed you have, you might be able to get that out with less damage[1]. But, when I took some of my quarry tiles off and cut out the screed, it broke the screed-concrete bond for several inches sideways in places (ie you might loosen the good bits of the floor).
[1] You'll want to sleeve the pipes to prevent copper corrosion if applicable - and more importantly, to allow the pipe to expand and move slightly.
If you can slot the screed with a disc cutter, it might chase out with minimal damage and less vibration. Or an SDS with a chasing chisel might work, assuming the screed's not too hard (mine varies between medium hard and mostly sand).
In your shoes, I would do an investigative cut first - maybe where you alread have loose blocks. Use a masonary drill on the top of the "concrete" to drill down 1-2", then see how easy it is to chisel out a small section. This will tell you how thick the screed is and also whether the DPM is just under it.
Don't let me stop you, but I still think chasing the walls would be less risky as you obviously have a quality floor - do you really want to disturb it?
Cheers
Tim
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Tim S wrote:

Thanks for all your comments, most appreciated. I'm off out now to saxophone quartet rehearsal so I will read it carefully tomorrow. Just wanted to point out though that there is "screed", and when I said "concrete floor" I was perhaps not being accurate enough. The question as to its depth still remains, however.
Michael
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" The radiators are rubbish anyway" - err - what can go wrong with a radiator - unless you want to change them for high output - or they are leaking.
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Do remember that where new pipes feed a new rad old pipes do not need to be removed from under the floor. Can you run vertically in eg a cupboard then cut into the walls behind the skirting boards?
Peter
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A wall can be repaired to be as good as new by a reasonable plasterer. Making a parquet floor like new again is more difficult. It is a feature to be treasured.
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Hi Michael,
In the last year I have done more or less exactly the same - 1970's bungalow, finger parquet block floor. We have just completed an extension as well, including extending the heating and domestic hot/cold water..
Our existing floors are: uninsulated concrete slab, with painted on bitumen DPC, then 25mm (ish) screed, and finally 10mm parquet blocks on more bitumen with what looks like a felt layer embedded in between. The existing copper pipes (heating and hot/cold services) were embedded directly into the 25mm screed.
On arrival two years ago the heating system was badly sludged, and almost cold in the bedrooms, so had to be chemically cleaned and flushed, which I did over a spring month. This solved the sludge problem, but revealed that the system had a number of tiny leaks, due presumably to corrosion and differential restrained movement in the concrete. At the same time I changed over to a wholly mains pressure heat bank hot and cold water system (due to a poor head from our one storey cold tank), which then showed the same pattern of small leaks in the pipework in the screed. I would suggest that if your pipes are directly buried in the screed they are at the end of their useful life, and you should probably consider another routing option. Trying to find the leaks in the screed is likely to be difficult, frustrating, ongoing, and to cause a lot of floor damage. Additionally, in a 60's house you are likely to have an uninsulated floor slab, and a lot of heat will be lost from pipes buried directly. This is wasteful (heating), and bloody annoying in the winter - run the kitchen tap to hot, turn off, 2 mins later it's cold again.
After considerable angst I bit the bullet and decided to renew the whole heating and water system - now done. This has well insulated pipes in the loft space in plastic, and drops in various places around the house in copper and plastic as suits the application. I know vertical drops are annoying, but they can mostly be hidden in cupboards etc - try to do drops to a group of rads, with short horizontal runs above skirting and though walls - if you are replacing rads (as we have), consider moving them to make grouping near a drop easier. Additionally, if you are re-piping the whole system you can split it into two or more zones, each with their own timer/stat.
As to the parquet - I've just laid a batch of reclaimed finger parquet in a corridor to the new extension, and have re-laid some of our existing parquet, which was loose. Both had bitumen adhesive on the back of the blocks, which was difficult to remove, so I've re-laid them on bitumen emulsion - ie paint on DPC liquid, which seems to work. Beware the fact that the blocks all seem the same size, but are not! Make sure the floor is flat if disturbed - use self levelling compound or similar. My laying method is to dry lay the blocks, sorting them for best fit and packing well together. Now tape over at right angles (I used parcel tape) to hold them together, and cut into suitable sections (1 ft squares or as you like), and lift out in sections. Now put a *good* layer of bitumen on the floor, restore the taped sections, and overlay with thin battens weighted with heavy blocks or similar. Leave 24 hours, remove the weights and tape, and clean up squooged bitumen with white spirit - it comes off quite easily at this stage.
Best of luck with all this - it's a *lot* of work, but if done will leave you with a much improved heating system, and beautiful floors.
Charles F
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CJF wrote:

[snippety snip]

Charles,
Thanks very much indeed for all that - I shall absorb and think further. Still planning where I can put drops and minimise wall/floor disruption...
Michael
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leave
Hope it was helpful,
Have a think, and if you need any further info you can get me directly by removing the bracketed part of my email addy.
Charles
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Been there done that. 1970's house with bitumen stuck down parquet floor with (leaking central heating) pipes embedded directly in the top layer concrete/screed.
The pipes were leaking due to tiny corrosion pin holes, eventually working its way between the parquet floor and causing an "always comes back" stain on the carpet.
I removed the parquet over the pipe run using knife, chisel and bolster. Came up quite easily where pipe was leaking. Pipe run easy to find easily found as floor was hot when CH was on and wood was stained. Used petrol to remove the bitumen glue, no problem. Had to angle grind out the pipe work as hammer and chisel would have taken too long. I bolted a wooden batton to the floor to act as an angle grinder guide, made a covering canopy of old sheets between two ladders, climbed underneath with sutiable protective gear and angle ground away. Hint, make sure you have enough spare angle grinder disks (or buy a diamond blade) as had to make a B&Q trip half way through cutting. Then used hammer and chisel (and more angle grinding) to remove the concrete and pipe. Use a wet/dry vacumm to suck the pipe work dry before smashing to pieces. My CH pipes went from back boiler across parquet floor lounge to radiator and to radiator in hall way via a buried T.
I replaced with 15mm copper pipes sleeved in 22m Hep2O push fit plumbing pipe. Had to have a solder joint in copper as run was a tad longer than 3m, the Hep20 was continuous. The termations where it comes out the floor and T piece were denzo taped as despite buying Hep2O rightangles + T peices you can't actually get the copper pipe in and solder the copper joints (...think about.....). I wanted to avoid the use of denzo tape but......The verticals out of the floor were sleeved with 22m Hep2O again I tested thorughly before covering the Hep2O with PVA and filled the groove with cement (+PVA...love PVA....). smoothed flat. Left for ages to dry....
I stuck the parquet floor back (I got bitumen type glue from Homebase) but some bits of wood were noticable bigger than others (due to damp ?), some were almost black with mould and rest of floor was not too great anyway, very large obvious gaps all over the place (I suspect fitted by previous bodging owners) as well as not really being finished at some edges ie no tiles fitted. I tried to get replacement wood pieces, but what I had was clearly "imperial size" and all replacement would have been "metric" and a lot of work sanding and shaping so in the end was carpeted over again. Also carpet considerably warmer.
If I was doing it again I would buy a diamond blade disk, probably use a bigger than 4" grinder and invest in an SDS hammer action chisel.
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