Emergency Insulation question

marielle

sinnerboy wrote: »

just upstairs . sounds like ground floor is ok

I'm probably being thick here but if you put insulation on top of UFH upstairs then another screed, aren't you preventing the heat from getting into the room at all? How would that help me? Unless you mean laying another layer of pipes above the layer of insulation?

sinnerboy

marielle wrote: »

Unless you mean laying another layer of pipes above the layer of insulation?

Yes this is what I mean

ardara1

Just throw'n my oar in here Sinner - If the temperature in the bedroom is 18 ish and below that 21 ish - is there not an argument that you don't really need insulation up there - the slab its self will be somewhere between these 2 temperatures.

Unless it's just to give more accurate control of the zones?

sinnerboy

How could the temp be 18 degrees up there ?

The first floor ufh will discharge all its heat energy into to the conc floor slab . An then into the supporting masonry structure . Unless the ufh is left on 24/7 the upper level will never heat up

ardara1

The typical temp in a bedroom (and for calc purposes in DEAP) is 18degrees - the occupants will get to this in some manner - even a dimplex heater. So if the temperature are similar - is there that much transfer up and down? The concrete floor will reach the UFH temp and radiate heat much like solar gain floor. - but perhaps up & down? Do know - just mulling ut over -
I'm not a great fan of underfloor heating anyway.

Mellor

Heat will always travel from hot to cold. If the slab was c.20 deg and the room was 18 deg. the pipes will be about 45 deg, so the delta temp is almost the same (25deg vrs 27deg), so alot of heat is going to pass into the slab, alot more than the room. Insulation here is a must.

ardara1

Mellor wrote: »

Heat will always travel from hot to cold. If the slab was c.20 deg and the room was 18 deg. the pipes will be about 45 deg, so the delta temp is almost the same (25deg vrs 27deg), so alot of heat is going to pass into the slab, alot more than the room. Insulation here is a must.

But the slab can't overheat surely? - will the slab not just 'radiate' that heat back into the room - or rooms?

sinnerboy

no . only if heat was on 24/7 . waste of energy . best thing is with UFH - keep fabric to be heated to min .

75mm screed with UFH takes about 1 hour for user to feel heat - if tiled - about 2 hours if timber floor / carpet . good thing about easi screed is 40mm reduces this time period .

UFH pipes direct onto conc floor slab - brrrrr !

DLBuild

Some great posts here folks.
Mind if I ask what the consensus is with regard to rads vs UFH on first floor. I'm pretty certain i'd like to have UFH downstairs and most flooring materials downstairs support this. However, upstairs where most of the day no heat is required would UFH be a bit of overkill? Would it be more economical to have rads coming on for an hour before bedtime upstairs?
The more i trawl through old threads the more confused i get with regard to all of these issues. I think Boards.ie should set up polls to gauge consensus on certain issues to help the poor old information seeker like myself.
Slainte.

Villain

Polls are easily abused by vested interests, ufh upstairs imo really only works when you have a concrete slab between floors and a lot of insulation directly under the piping, also a lot of people only use upstairs for bedrooms which are only used at night, so trying to keep heat upstairs while not having the heating on all the time can be a tough juggling task.

The main advantage imo is having heated floors when you step out of bed or especially when you go to the bathroom, however there are electric UFH mats which can be used for the bathroom, type of flooring cover is a bit more restricted too.

sinnerboy

DLBuild wrote: »

Some great posts here folks.
Mind if I ask what the consensus is with regard to rads vs UFH on first floor. I'm pretty certain i'd like to have UFH downstairs and most flooring materials downstairs support this. However, upstairs where most of the day no heat is required would UFH be a bit of overkill? Would it be more economical to have rads coming on for an hour before bedtime upstairs?
The more i trawl through old threads the more confused i get with regard to all of these issues. I think Boards.ie should set up polls to gauge consensus on certain issues to help the poor old information seeker like myself.
Slainte.

About 4 / 5 of our clients go for UFH ground floor - rads first floor . for a no of reasons

UFH is a slow response but this ok in the daytime spaces . Families with small kids and varying bedtimes like the flexibility / responsiveness of rads - esp with TRV's . If cold night , turn first floor stat up and 20 mins later - all nice and warm up there . If too hot - vice versa .

UFH means furniture layout is "free-er" without rads . Less of a big deal with bedrooms .

marielle

Can I ask about a product that I actually had thought of using upstairs to start with but then decided to go with a screed instead.:mad: It is called Heatrack : http://snipurl.com/1zvnj and basically the pipes are stuck onto a board with already has grooves in it. No need for screed, you just stick your wood floor finish on top. Quick to install as well... could that be the answer to my problems?

sinnerboy

marielle wrote: »

Can I ask about a product that I actually had thought of using upstairs to start with but then decided to go with a screed instead.:mad: It is called Heatrack : http://snipurl.com/1zvnj and basically the pipes are stuck onto a board with already has grooves in it. No need for screed, you just stick your wood floor finish on top. Quick to install as well... could that be the answer to my problems?

you needed a screed any way to knit the ( presumably precast conc ? ) floor slabs together . placing the UFH pipes in there was the boo boo

this is an alternative to the product you posted

http://www.tem.ie/heat_dist_under.htm

a product like these will eliminate the screed and speed up the response time ( the time lag between heat on and you feeling the heat ) .

But you still need the insulation layer , so you don't waste energy heating the fabric of your floor structure .

ardara1

Villain wrote: »

Polls are easily abused by vested interests, ufh upstairs imo really only works when you have a concrete slab between floors and a lot of insulation directly under the piping, also a lot of people only use upstairs for bedrooms which are only used at night, so trying to keep heat upstairs while not having the heating on all the time can be a tough juggling task.

The main advantage imo is having heated floors when you step out of bed or especially when you go to the bathroom, however there are electric UFH mats which can be used for the bathroom, type of flooring cover is a bit more restricted too.

Would slippers not be cheaper?

marielle

sinnerboy wrote: »

you needed a screed any way to knit the ( presumably precast conc ? ) floor slabs together . placing the UFH pipes in there was the boo boo

this is an alternative to the product you posted

http://www.tem.ie/heat_dist_under.htm

a product like these will eliminate the screed and speed up the response time ( the time lag between heat on and you feeling the heat ) .

But you still need the insulation layer , so you don't waste energy heating the fabric of your floor structure .

Fair enough i still would need insulation underneath it but at least i would be loosing less than 90mm overall though! Also the system would be way more responsive than a normal screed system. Can I mention the dreaded word "foil" to use as an insulation under this or will you shoot me?:p

sinnerboy

marielle wrote: »

Can I mention the dreaded word "foil" to use as an insulation under this or will you shoot me?:p

no . I might send you an electric blanket and some cocoa

Mellor

marielle wrote: »

Can I mention the dreaded word "foil" to use as an insulation under this or will you shoot me?:p

This would be the worse application of foil insulation, which is already a badly performing insulation.

sinnerboy wrote: »

you needed a screed any way to knit the ( presumably precast conc ? ) floor slabs together .

I think the product posted was designed to be used over timber floors eliminating the need for a screed.

When there is insulation between the screed and precast slab, does the screed haves any structural benefit. I wouldn't of thought so

galwaytt

Mellor wrote: »

I think the product posted was designed to be used over timber floors eliminating the need for a screed.

We have done a pair of semi's with it, and it seems to work very well.

marielle

galwaytt wrote: »

We have done a pair of semi's with it, and it seems to work very well.

Can I ask what you used under them? Did you go for the 50mm KS or did it come with its own insualtion?

sinnerboy

Mellor wrote: »

I think the product posted was designed to be used over timber floors eliminating the need for a screed.

It can also be used in OP situtaion

Mellor wrote: »

When there is insulation between the screed and precast slab, does the screed haves any structural benefit. I wouldn't of thought so

wouldn't do this anyway . ufh in upper level pc floor is

UFH pipes in screed ( or special boards )
insulation
structural screed
pc slabs

DLBuild

Sinnerboy, Is the structural screen between the slabs and the insulation a must? What purpose does this serve?

sinnerboy

the structural screed ties the precast floor slabs together - so you end up with a floor-plate , not a collection of independent slabs .

Mellor

It also allows you to use thinner slabs, of course the fact that you use a screed returns this. I wouldn't say its essential, we have used precast wideslab units that where larger and more solid than hollowcore slabs, in there a structural screed was not needed

DLBuild

I've got 200mm pre stressed hollow core slabs on order. I believe these are quite strong i.e. no need for acros etc. Would i be correct to assume that I don't need a screed for structural reasons on these?

ircoha

DLBuild wrote: »

I've got 200mm pre stressed hollow core slabs on order. I believe these are quite strong i.e. no need for acros etc. Would i be correct to assume that I don't need a screed for structural reasons on these?

This is an IMPORTANT issue for ur designer as it is a function of the span, what loads are applied from above etc.
DONT assume in this case please:(

DLBuild

Okay yeah, I should have added that the company providing the slabs have specified the depth of slab etc based on my plans. I will ask a few questions but would be relatively confident things are done correctly.

ircoha

DLBuild wrote: »

Okay yeah, I should have added that the company providing the slabs have specified the depth of slab etc based on my plans. I will ask a few questions but would be relatively confident things are done correctly.

Thanks, u need to be certain, also re acrows
In relation to the use of acrows, u need to consider the possibility of a load of concrete blocks being places on the floor by a transporter etc during construction.

I have many many years experince in the pcast business and you cant be too careful

sinnerboy

DLBuild wrote: »

Okay yeah, I should have added that the company providing the slabs have specified the depth of slab etc based on my plans. I will ask a few questions but would be relatively confident things are done correctly.

based on what ? are you going to live under these things ? or just some poor unfortunate tenants ?

Here's a novel idea - hire professional advice . Posting queries here on this ( or any thing else ) is a very very poor substitute

marielle

sydthebeat wrote: »

have you no professional engaged to inspect or supervise this build?

Firstly, he should not have incorporated 60mm polystyrene into the walls. That hasnt been acceptable for 5 years now. Its a good job you demanded 50mm insulated plasterboard, this may bring you up to minimum regulations. A quick calculation of 60 EPS and 47.5mm insulated plasterboard in a trad cavity wall gives a u value of 0.26.. .thats just below the min of 0.27....
not exactly optimal when you are installing air to water HP and UFH.

The HRV system is a must.

I completely agree with sinnerboy re multifoils, they are unprovable as an insulator... and they are an expensive vapour check membrane.

I wouldnt bother insulating the ceiling downstairs since there is no insulation below the screen on the first floor.

You need to give more info as to the exact make up of the ground floor construction.


But most important to guarantee the best performance at this stage is to hire a competent professional to inspect this 'old school' guys work......

ok, I went and tried to calculate a U value figure for my walls and here is what I came up with. Can anyone tell me if I'm missing something here?
I am adding the thermal resistance of all the elements that make up my wall. From the outside :
Thermal resistance or R for the outside wall : 0.06
R for 100mm concrete block wall = 0.09
R for the cavity = 0.18
R for 65mm Pearl expanded polystyrene cavity insulation = 2.096
R for 100mm concrete block wall= 0.09
R for 38mm PU insulation = 1.52
R for 12.5mm plasterboard = 0.078
R for inside surface = 0.12
This gives me a total Resistance for the wall of 4.234 and therefore a u-value of 0.236.
Am i correct? And if so, isn't that well below the 0.27? Is this considered good or not?

ardara1

Hi Marielle -
Your internal resistance should be 0.13
external - 0.04

I make it 0.24 - if the PU is directly to the wall - if on dabs or battens, you've another (bridged) cavity to include.