Possible to redo concrete floor or too costly?

Hi

I live in a property that has its gas supplied by a shared LPG tank underground at the front of the property.

I've considered getting a heat pump installed but our property in its current state just isn't suited for one. Even with the gas boiler the house isn't that warm so I can't imagine what it would be like if we got a heat pump installed. We have thick loft insulation and cavity wall insulation already so I don't think there is an easy fix for it.

If we were to get a heat pump I feel it would only be suitable if we were to dig up the concrete floor, super insulate it and lay underfloor heating pipes at the same time that could be ran from the heat pump. We would be doing this for two reasons: to get off the LPG and to make the property more comfortable to be in (it's rather cold at the moment).

I know this would involve ripping out everything on the ground floor including the kitchen, but if we were to do this we would do it as part of a bigger job which would include a new kitchen and flooring.

What I'm really trying to find out is:

A) Does anyone know how much roughly to dig up, insulate and relay concrete floor? Our ground floor is around 60 SQM, I don't know if digging it up will be a few grand or 20 grand
B) Has anyone done anything like this before and has some advice?

Is it better just to move? :(

Thanks!

Comments

  • Breaking out a concrete floor is noisy and the structure born vibration could be a problem, are you detatched or joined to someone else? If your not detatched you need to discuss the noise and length of works with them.

    Why not use radiators with the heatpump, they work fine you just need bigger ones as your flow temperature are lower and hence heat output is reduced.
    I have a lot of problems with my neighbours, they hammer and bang on the walls sometimes until 2 or 3 in the morning - some nights I can hardly hear myself drilling ;)
  • simons_s
    simons_s Posts: 33
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    Thanks for the reply Homersimpson

    We're in a detached property but I would have a word with the neighbours before we did anything as they're still quite close.

    Heat pump with radiators is certainly an option I'm just worried slightly larger radiators are not going to be enough as our property is not warm even with an LPG boiler on full temp.

    I have received a couple of heat pumps quotes in the past when we've considered it and both companies said we'd have to run the heat pump at around 50-55c even with larger radiators. At that flow temp it would not be efficient enough to make it worth it. However with UFH and correct insulation in the floor I believe a heat pump could be efficient for us long term.
  • tacpot12
    tacpot12 Posts: 7,894
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    Heat pumps do seem to have more than their fair share of problems, and few that have installed them seem to find they save money. I think I would be inclined to do all the improvements you propose to your home, and stick with LPG for a while, while you monitor the amount of LPG you are still using. If you are using very little LPG, installing a heat pump might work. I think I would keep the LPG infrastructure until you are certain the heat pump is working well. Underfloor heating in the slab is the way to go for heating the ground floor.

    I had the ground floor in a Victorian cottage (about 40sq meters) dug out, and insulation and a new concrete slab laid, unfortunately this was nearly 20 years ago and there was no existing slab; the existing floor was quarry tile laid on bear earth. But it don't take the builder long to dig the out the material, although this will depend to some degree on how much insulation you are going to lay (get photos of the insulation and a ruler before the slab is poured though, as in future an Energy Assessment might want proof of the thickness of insulation that is under the slab.

    My guess is that it will be a £2-3 thousand pounds, definitely not £20K.
    The comments I post are my personal opinion. While I try to check everything is correct before posting, I can and do make mistakes, so always try to check official information sources before relying on my posts.
  • Only about 10% of heat is normally lost through the floor, although a cold floor can certainly make a house feel colder.

    Do you have enough ceiling height (and door height, to avoid having to cut and raise indoor lintels) to insulate above the existing floor? Eg Styrofloor starts at 43mm and combines insulation and chipboard.

    With thick carpets that could feel a lot more cosy and you'd only have to shorten your internal doors by about 2"

    I'd also look at where else heat loss is occurring - draughts and external doors can be big culprits. Also some cavity wall insulation isn't that great and external wall cladding might also be worth considering.

    For underfloor heating to be cost effective even with a heat pump you need a lot of underfloor insulation.
    A kind word lasts a minute, a skelped erse is sair for a day.
  • simons_s
    simons_s Posts: 33
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    @tacpot12

    That sounds like good advice. Keeping the LPG boiler sounds like a good idea. If your price guess is accurate, I would see no reason at all not to do this as part of a bigger refurbishment project.

    I'm not in a position to get quotes at the moment as I'm not in a position to the work for another 6 months at least. I don't want to waste builders time. I just want to get an idea of it we can actually do this or wether we should look at moving instead. Everything else about the property is great apart from the heating so we don't really want to move.

    And thanks for the tip about getting photos. I would never have thought of doing that.

    @Owain

    We do have enough ceiling height but unfortunately we do not have any extra space between the concrete and the front door to the house. The bottom of our front door is about 1 inch above our laminate flooring.

    How would I go about finding where heat is being lost? Would I need a thermal camera to do something like that? If we decide to do the work we would get new windows at the same time as our double glazing is getting on for 20 years old now.

    If we were going to the trouble of digging up the floor, I would imagine we would put a heck of a lot of insulation under there whilst we have the chance to!

    Thanks both!
  • One of the problems with heat pumps is that they get less efficent as it gets colder outside (the coefficent of performance - COP drops).

    They also have to carry out a defrost cycle every so often to stop them freezing up when its really cold, while they are doing this they can't heat although the cycle isn't massivly long but inconvenient if you need heat.

    We specified lots of them but usually for new housing estates where the cost of getting a gas supply was prohibitive.

    Beware that some units have an electric top up unit so when its really cold outside and they don't produce enough heat the electric heater makes up the short fall (at huge cost).
    I have a lot of problems with my neighbours, they hammer and bang on the walls sometimes until 2 or 3 in the morning - some nights I can hardly hear myself drilling ;)
  • You would need to shorten or get a new front door, or put a small ramp up to the insulated part of the floor.

    A thermal camera might be interesting if you can find/borrow/hire one cheaply.
    A kind word lasts a minute, a skelped erse is sair for a day.
  • Mistral001
    Mistral001 Posts: 5,346
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    edited 14 January 2019 at 11:06AM
    I would just get quotes for digging up and replacing the floor. If you can get all the furniture (including kitchen units) removed and vacate the premises for the duration of the work then you could get quite competitive prices.

    A big factor for a contractor pricing such a job will be unknowns in the form of any heating or water pipes under the floor and the type of floor that is presently there. If the house is more than say 50 or 60 years old then there is likely to be only a couple of inches of weak concrete which will be easy to remove and will not cost much to dispose of, but if the house is built later than that there could be thicker, stronger concrete there that will be costly to remove and dispose of.

    The more the contractor pricing the job knows about the existing floor construction and heating and water pipes (and maybe electrical cables) etc under the floor it before pricing, the more competitive will be the quote. Beware of the contractor just pricing for removing the floor and then charging extras for dealing with the pipes and other "unknowns".

    PS. The most economically way to do this job might be on materials plus labour costs basis because of the unknowns regarding the existing floor and what is under it - if you have a builder that you have worked with before on that basis.
  • Depending on square footage price wise, but it is a huge job. Just digging out the existing floor and re-pouring will be pushing towards five figures. You'll never recoup that in energy savings, and very little heat actually escapes through there comparatively to roof/walls.


    You could fit some boards down and screed depending on your existing floor level but still a costly and messy affair.


    Nice thick underlay will solve your problem and spend your money insulating the parts that make a real difference
  • simons_s
    simons_s Posts: 33
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    Thanks for the reply armchaireconomist

    I would not consider getting this work done if it does cost five figures. If it was a few thousand on top work I'm already getting done, I would do it.

    Perhaps thick underlay and carpet will in fact solve the problem. At the moment we have quite thin laminate with no insulation under it.

    It's not 100% about cutting the cost of the energy bill each month. It's just as much about making the house a pleasant place to be in winter. It's just not confutable as it is.
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