In Wall heating - Discussion

[zeus]

Hi All

Reading the post on DIY retrofit U/F heating on an existing concrete slab in a modern low ceiling house reminded me of a thought I had a while back, but like normal, did absolutely nothing about   .... so here goes, and feel free to laugh if you feel it's necessary ..... underfloor heating in a wall ......  

Okay, If you're still reading and interested I'll expand the reasoning. Picture a modern(ish) concrete slab house roughly 20mx10m with standard ceiling heights, all internal walls downstairs (and some upstairs) of solid construction, a large central hallway, standard door heights .... oh, and a 'better half' (she who must be obeyed) who has drawn the line at messing up the decor in any room, other that the hallway, which is in 'dire need' of redecoration (whatever that means .... looks perfectly acceptable to me  ) .... so without destroying part of the concrete pad, or having a step into every room off the hall, the idea of (wet) U/F heating is off the cards.

Picture painted ... Ding .... (rare)idea ..... use the mass in the walls and leave the floor level where it is.

After thinking for a while (in the pub, of course), the idea of chasing out the walls, mounting grooved spreader plates to the wall, pex pipe (with a bleed valve at the high point)  and then clad with large limestone panels (she who must be obeyed likes the idea of a 'limestone block' feature wall) ......

Considering that this was thought up after a considerable intake of ale, has anyone else ever had a similar idea and maybe gone a step further and done it ?


Regards
Zeus

[desperate]

Zeus, wotcha

In theory it could be done, after all the Roman Hypocaust system used flues built into the walls from under the floor to utilise the waste heat in the walls..............BUT can you imagine how easy it would be to drill a hole in the pipework when fixing shelves, pictures etc??  , it's bad enough trying not to hit the sparkys cabling all over the place .
I think also the exterior walls would need a very high level of insulation to keep the heatloss to an acceptable level, as in effect you would have an internal wall surface temperature of 35-40 deg c instead of about 20, hence a much higher difference between the internal and external surface temp. I spose if you only heated internal walls heatloss could be minimised.

Bottoms up old chap
Desperate

[Rooster]

I certainly had the same thoughts, and nearly did it but sold the house instead!!!

'In wall piped radiant heating' is certainly done, you can also put it in the ceiling. A lot of the UFH kit is sold as suitable for walls as well.

You can buy specific kit such as the 'Variotherm Easyflex' ..... http://www.constructionresources.com/products/services/radiantheating.asp for solid walls and there are kits for timber stud walls as well.

Not sure that you would need the limestone block, just render it!

The question is going to be whether you have enough wall space made up of walls adjoining your hall to give sufficient heat for all the rooms, the hall will certainly be warm, maybe pipe a bit of warm air from hall to other rooms as well!

Interested to know how you get on as there is not much on the net about it but it does seem to make a lot of sense for retrofits.

[zeus]

Desperate, Rooster (/All)

Thanks for replies, thought I couldn't be the first to think of it ..... so it's already an invented wheel 

Regarding outside walls, really it's just a door and a window, so approx 2.5m of wall length, there's probably another 3-4 metres of wall to an internal garage then there's probably something like another 14m of internal solid wall of which I was thinking of heating about 8, so around 20sqm (Double sided - x2 ?).

The idea of using the metal spreader plates was to soak heat away from the pex pipe as quickly as possible, most of the heat transferred directly through the stone facing, but a good proportion being taken into the wall's thermal mass, providing some heat to the rooms on the other side.

The idea of using the stone facing was due to the use of the spreader plates ... I reckoned that getting any form of 'plaster' type covering would simply not adhere (I did think of using a metal mesh to spread the heat to overcome this, but decided against it), so opted for a solid solution. The idea would be to utilise a facing, probably around 1/2" ... there's a local supplier we've seen who can supply large floor to ceiling stone panels, although at this kind of size they would need to be more than 1/2" .

I guess that one of the main reasons that it never went ahead was that I couldn't find any information to give me the confidence to invest, I'd reckon that the setup would probably provide around 3kW of background heat, but then again, I'd be interested in anyone else's thoughts.


Regards
Z
     

[daftlad]

, it's bad enough trying not to hit the sparkys cabling all over the place .

So it's you is it, drilling holes in our cables. The trick is to NOT drill holes above or below switches and sockets, that's where the cables go. 
You could stick a picture rail up? 

I think someone on the forum has put pipes in walls, have a poke around the "show us yours" section, it sounds like a good idea to me (internal walls only) I am not sure if you would even need the spreader plates (whatever they are!)
ta ta

[dhaslam]

I would imagine that the heat output would be similar to  underfloor, ie about 6watts per metre  of pipe at 35C.  I wonder if you should think of a thin layer of insulation in the hall  and finish with plasterboard or tiles.   This would concentrate  much more heat into the rooms.     It all sounds like a  good low cost  option, specially when the hallway needs attention anyway.           

[daftlad]

Found it.
Billi seems to have put some pipes in his wall.
http://www.navitron.org.uk/forum/index.php/topic,2188.105.html
There is a photo of some plastering going on and you can just see the pipes on the right hand side of the wall.
ta ta

[desperate]

Daftlad,

Dont tell me you sparkys put your cables in the protected zones as well

Desp

[daftlad]

Daftlad,

Dont tell me you sparkys put your cables in the protected zones as well

Desp

I used to........... honest. 
But now that I am retired from first fix, etc etc...
ta ta
Sorry for hijacking the thread but any excuse to have a go at the plumber has to be taken. 

[desperate]

anyway whats the problem?? they dont leak or anything, no matter how many holes they got in em, daft bloomin sparks...........

Desp

[tony.]

what about a heated ceiling?

fitted a few of them in offices a number of years ago.

tony

[wookey]

Heated ceilings make for hot heads = uncomfortable. There are a number of houses in Cambourn near Cambridge like that. Not very popular with teh residents (electric, so expensive and uncomfortable).

Variotherm do both panels and clipped-pipe wall heating systems: http://www.constructionresources.com/products/services/variotherm_modular_wall.asp?PageCategoryID=19

[Finlay]

Have you thought about skirting radiators?  You can buy aluminium extruded skirting boards with water channels inside which act as a low level 'wall' radiator, about 170 watts/metre I think.  Try looking here <http://www.heatprofile.co.uk/Flattened/tech.html>