UnderFloor Heating and increase room height

thomasjvi

Dear Friends, I want to increase the ground floor height and do underfloor heating. It is in Lucan and have around 800 Sqft ground floor area. The floor is using carpet now and under the carpet there is concrete with around 18CM thickness. I want to dig 6-7 CM concrete down + and do underfloor heating. This is a semidetached house and the floor including kitchen,livingroom and dining room. Any Idea how much it will Cost
Thanks in Advance Eoin

893bet

What insulation is currently under the floor?

thomasjvi

Looks like there is no insulation.. Thick wood(around 2-3 cm) and then carpet on top of that. The problem is digging the concrete for 6-7 cm all around 800 Sq.Ft and levelling the floor.

893bet

If there is no insulation under the floor then there is little point with under floor heating. I suspect you will need to dig down 10-12 inches to provide 120-150mm insulation and then put in the underfloor heating.

Little point just putting it in as it stands.

BryanF

Move out, find somewhere to rent,
Turn of gas, water, electricity,plug drains,
Remove and Store all doors, protect pretty much everything, (be prepared to replace or at least temporarily remove everything allowing for % breakage) skirting/architraves/ sockets, wiring, plumbing, kitchen, etc

Get skip,
Dig out floor,
Remove down ~400 mm
Assuming ground is ok, install sump system, add layer of hardcore, followed by sand, radon barrier, 150mm PIR insulation, ufh system, install concrete screed. Then let it slowly dry out.

DIY maybe 5k and two months labour

Contractor depending on access 10/15k

Both excluding (heating system, and all decoration)

thomasjvi

Further investigation looks like there is some kind of insulation under the concrete(not sure as I bought this a year before). The current concrete under the carpet has 17-18 cm thickness. My main question is, can I dig out and remove 7-8 cm and keep remaining 10cm thickness of concrete as it is ,so that I will get a better room height. Will this cause any structural damage? If so , for removing 8cm thickness of concrete how much I need to expect ? A ballpark figure..

Gumbo

thomasjvi wrote: »

Further investigation looks like there is some kind of insulation under the concrete(not sure as I bought this a year before). The current concrete under the carpet has 17-18 cm thickness. My main question is, can I dig out and remove 7-8 cm and keep remaining 10cm thickness of concrete as it is ,so that I will get a better room height. Will this cause any structural damage? If so , for removing 8cm thickness of concrete how much I need to expect ? A ballpark figure..

You want to reduce a 180mm concrete floor slab down to 100mm?
Serious breach of Part A of the Building Regulations in my opinion as the span of the slab may mean the thickness is too little and may not comply with the original design parameters.

What has your engineer said?

BryanF

thomasjvi wrote: »

Further investigation looks like there is some kind of insulation under the concrete(not sure as I bought this a year before). The current concrete under the carpet has 17-18 cm thickness.


My main question is, can I dig out and remove 7-8 cm and keep remaining 10cm thickness of concrete as it is ,so that I will get a better room height.
.

No! forget it, how would even go about doing this? Without making sh1te of everything?

.

Will this cause any structural damage? .

Yes.

If so , for removing 8cm thickness of concrete how much I need to expect ? A ballpark figure..

did you read my earlier post?

Metric Tensor

It could be a non structural screed but it could be a structural slab. You need an engineer to check this ....

BUT.

It's a mad plan anyway:

You'd balls up your stairs.
All your doors would be a non-standard height
Your fire escape windows (if they exist) might no longer comply with the fire standards.
Your new floor level might be subject to dampness depending on the wall construction.
Have you got a fireplace? What will you do with the hearth?

It's not a runner unless you are totally gutting the house top to bottom and even then it had a huge amount of knock on problems.

adam88

Bear with me here guys. I'm doing something similiar. Totally gutting a 1970's bungalow. Want to put underfloor heating throughout the house. Just at the start of this project but don't want to ask a plumber face to face incase I look like a total numpty. But do you need a special boiler for underfloor heating or will your regular boiler used for normal radiators do you ???

murphaph

adam88 wrote: »

Bear with me here guys. I'm doing something similiar. Totally gutting a 1970's bungalow. Want to put underfloor heating throughout the house. Just at the start of this project but don't want to ask a plumber face to face incase I look like a total numpty. But do you need a special boiler for underfloor heating or will your regular boiler used for normal radiators do you ???

You can use any heat source you like more or less including a gas or oil boiler but look at models that modulate. Be sure to use narrow enough pipe spacing in your UFH so you retain the option of going low temp even if you don't at the beginning. I used 100mm spacing throughout for our low temp system.

air

You can retain the existing boiler but will need to install a mixing valve to reduce the flow temperature.

adam88

Debating whether to go fully ufh or just ufh in the large living space and rads in the B/rooms. Only reason I'd put rads in the rooms is to be able to put in towel rads in the bathrooms and ensuites

adam88

murphaph wrote: »

You can use any heat source you like more or less including a gas or oil boiler but look at models that modulate. Be sure to use narrow enough pipe spacing in your UFH so you retain the option of going low temp even if you don't at the beginning. I used 100mm spacing throughout for our low temp system.

When you say low temp do you mean the actual room temp or the temp that the boiler heats the water at?

I'm not a fan of hot rooms and I really only like to take the chill out of the room so that it's comfortable and your not close to sweating

JonathonS

adam88 wrote: »

Debating whether to go fully ufh or just ufh in the large living space and rads in the B/rooms. Only reason I'd put rads in the rooms is to be able to put in towel rads in the bathrooms and ensuites

Depending on how your house is configured and how airtight and well insulated it is you may not need rads in the bedrooms. Sufficient heat will rise from the ground floor area. In that case you could run a UFH loop to the towel rail.

murphaph

adam88 wrote: »

When you say low temp do you mean the actual room temp or the temp that the boiler heats the water at?

The flow temp of the water. Please note a low temp system will require you to have a well insulated house with good airtightness, but you are completely renovating so this should be on the agenda anyway and should take precedence over any heating system stuff.

JonathonS

BryanF wrote: »

...install sump system

Bryan, this is something I have not seen mentioned before when looking at retro-fit UFH. Please expand - what is the purpose and what is involved in installation?

murphaph

JonathonS wrote: »

Depending on how your house is configured and how airtight and well insulated it is you may not need rads in the bedrooms. Sufficient heat will rise from the ground floor area. In that case you could run a UFH loop to the towel rail.

I decided against this. I didn't want a steel rad rusting slowly into my otherwise (almost) completely plastic and stainless steel system. I also read that low temps encourage rust.

Even if I had done it it wouldn't have worked too well because the flow temps are well below body temp they'd never warm a towel anyway.

I'd keep it all separate and use an oil filled towel rail with immersion element on a timer to heat towels before bath time if towel rails are important.

adam88

Can you use all types of floor covering with ufh I.e. Carpet, vinyl

I know wood and tiles are ideal

BryanF

JonathonS wrote: »

Bryan, this is something I have not seen mentioned before when looking at retro-fit UFH. Please expand - what is the purpose and what is involved in installation?

Radon. Building regs. http://www.housing.gov.ie/sites/default/files/migrated-files/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad%2C1642%2Cen.pdf

Nothing to do with ufh, it's to do with lifting and reinstating concrete floors.