Hot Water Underfloor Heating

[hally78]

have a query on my hot water underfloor heating. do I put in vents in the floor for this type of system or not. i was led to believe it was just the air system i needed vents for??? thanks for help

Charlotte (building own house)

 

[migoplumber]

there is a vent on your under floor heating system manifold,
you need to explain your problem a little more

good luck
shaun

 

[hally78]

sorry shaun, will try again. i am putting in underfloor heating which is using hot water instead of air. i was led to believe that with the hot water system i didnt need to put vents into the floors (to possibly let heat out?) as it is not needed. i was also told that the air variety did need the vents and i specifically dont want vents all over the floor and thought that this particular underfloor heating did not require (exit) vents.

i dont want to have to cut round them when putting my flooring down.

does this make more sense?

 

[migoplumber]

underfloor heating usually is just a pipe under the floor full of hot water that circulates to a manifold. a manifold is just the connection from the boiler to a distribution point. your manifold will feed various rooms and circuits, the heat being fed into each circuit is controlled by a thermostat and electric valve (the valve sat on the manifold, the thermostat telling the valve to open and close)
the manifold should be higher up than all the zones it supplies, and automatically vents any air out of the system
there is no need for vents in the floor. ive never heard of that.

if your not totally sure of what your doing get a pro in to give you some advice. you can still do the work, but he can help you get it right. remeber your burying your system in a concrete floor, do it wrong and youll be digging floors up.
get help.

good luck

shaun

 

[hally78]

ok i understand that, but the underfloor heating will be going under a suspended floor and not in concrete at all. so there is the space for air flow. does that mean i need to have the vents in the floor to have the air flow escape or can it be closed over by floor boards and no air flow vents?

 

[migoplumber]

charlotte. underfloor heating is not installed suspended, its encased. celotex or equivalent underneath normally 50mm then your pipework, then your cover, followed by finished surface.
you maybe doing something new that im not aware of! are you worried about ventilation or air vents.
show us a diagram or plan


shaun

 

[hally78]

this is what i am having
Suspended Floor System Design

UFCH can be installed simply between the joists of a suspended floor, either from above or from below. Alternatively UFCH pipes can be laid between battens above the joists. Standard tongue and groove floor board is laid above the system and any floor covering may be used.

all i am trying to understand is if i need to add any type of vents/grates in the floor to allow any heat to come up ( i was previously under the impression i didnt) or to allow air to circulate up through and into the room (again i was under the impression i didnt)
i am having floor layed shortly and i dont want to have any (what i consider ugly) vents/grates in the floor if it is not needed.

sorry i am so rubbish at explaining

 

[migoplumber]

you are worried about ventilation.

the heat in the ufch will rise through your flooring to the finished surface.

no air vents required.

it is not a very effiecient under floor heating system as there will be plenty of heat lost in the joist space, swallowed up buy your house ventilation.

reconsider set up. maybe electric roll on top of your floorboards, umderneath finished surface, be it tiles or wood flooring.

shaun

wait for some other advice too!!

 

[Mike Jackson]

As long as there is plenty of insulation between the joists there won't be too much heat loss.

Mike

 

[stevetheplumber]

no no vents are requiered heat transfers through the floor covering if its an up stairs loor there will be no heat loss as the cavities between joists are not vented
on a ventilated suspende floor you will need to fix insulation between each joist normally polystyrene slabs

 

[Bernie2]

It depends, if the floor covering lets heat through more readily than the surface underneath the pipes.

Have a look at the heat transmission values of the floor and compare it with the space under the pipes. You don't say whether the suspended floor is a first floor with a ceiling underneath or a ground floor with a void underneath?

If its a void the chances are you will loose a lot of heat through the underfloor exterior ventialtion grills. If its a 1st floor, floor, some ceilings can take the heat other's can't it depends, but the heat may radiate both ways, once again it depends on the value of each material.

Just think of yourself as a btu and you want to escape the easiest way possible, if you can work that out then that is where you put the insulation, to stop it escaping.

 

[migoplumber]

Your right mike with the insulation, but i dont think ive ever seen a standard house, with insulation between joists, between ground and 1st floor. I just assumed it didnt have any.
Charlotte, make sure you insulate between your joists and around your pipework!

shaun

 

[Deleted member 2053]

Generally the heating pipework is installed from underneath after the 1st floor has been laid. There are metal plates that screw to the underside of the floor and there are holders on these plates for the pipework. These plates have the advantage of conducting some of the heat from the pipe and spreading it. Be careful that your pipe runs through joists do not compromise the structural integrity. Some of these modern joists are very fussy about where you can and cannot make holes.
And yes you will need plenty of rockwool insulation under the pipework above the plasterboard for the ground floor ceiling.