Do professionals need to Insulate pipes/floors - building regulation requirements

Discussion in 'Builders' Talk' started by Maryfire12, Dec 21, 2022.

  1. Maryfire12

    Maryfire12 New Member

    Hi, I’d like some clarity please on building regulation requirements in terms of insulation.

    For context, I live in a Victorian terrace with suspended Victorian floorboards (void under the floor for airflow). Recently we had the following work done on our downstairs living room: including replacement of around 70% of the joists under the floor which had evidence of wood rot and moving/installing additional radiators and building a stud wall between the living room and hallway. They also added a damp proof membrane under plasterboard around the bay window due to damp.

    I noticed that neither the new plumbing for the radiators or the new stud wall are insulated. Insulation under the floor was never discussed or suggested - although the builders knew we were planning on putting engineered flooring on top and our void is very shallow (maybe 40cm deep) so it’s possible insulation wouldn’t be appropriate under our floor.

    Having since checked building regs, it suggests that insulation should be added where the floor is taken up and/or new central heating pipes are laid. Can anyone familiar with the building regs clarify if the builders should have insulated as part of the works or did I miss something by not discussing this with them at the time?
     
    Last edited: Dec 21, 2022
  2. stevie22

    stevie22 Screwfix Select

    If you alter more than a given percent of a thermal element (25% IIRC) then you're supposed to upgrade it. Floor is a thermal element.

    What you have agreed with your builder is another matter: was it discussed? Were Building Control involved? Builder isn't going to do it for love.

    Internal stud wall doesn't need insulation as warm each side, but normal to put glass fibre, or better Rockwool, inside to reduce sound transmission.

    Insulating pipes under floors is another matter: should definitely be done
     
    rogerk101 likes this.
  3. Mark Griffiths

    Mark Griffiths Active Member

    My experience with builders is that they don't want to waste their time with insulation. I had a section of water damaged ceiling replaced under a pitched roof a while ago which had no insulation behind it. They were just going to replace the plasterboard without insulation until I questioned it. Glad I did because it's made a huge difference.

    If I were you, I'd pull the floor back up and insulate the void and pipework.

    (edit - actually, I wouldn't have let them put the new floor down without insulation, but you get the point).
     
  4. Maryfire12

    Maryfire12 New Member


    Building control not notified as there was nothing being done that didn’t require permission and all falls under maintenance I believe. Over half the floor joists (not top layer) definitely replaced but I’ve also been told by other sources that if your void is shallow, it’s best to keep the airflow as much as possible. No rock wool or anything in the stud but are they required to under regulation?

    I’m not sure what the pipes are made out of - either some flexible poly plastic or maybe polybutylene, I’d have to check. Apologies I tried to attach a picture but can’t seem to get it to work.

    If I went back to my builder to query this, am I right I understanding, it should have been insulated as per regulation under 4.24 document L: conservation of fuel and power ?
    https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1082462/ADL1_revised.pdf
     
  5. Maryfire12

    Maryfire12 New Member

    I guess my question is, if they are a legitimate company, should they be doing it as per what appears to be code without it being raised?

    I’m still deciding if I should push it re the floor insulation because the airflow was an issue previously and I had an additional air brick added and it’s possible this would be their reason also. I’m also getting new flooring and plywood laid on top so this would stop any kind of draft. Based on the earlier response, I’ll definitely raise the pipes.
     
  6. Abrickie

    Abrickie Screwfix Select

    See @stevie22 post, this is notifiable work the floor should have been insulated to current regs ( or as close as possible). Imho the fact that the builder didn’t point this out, speaks for itself. The requirement for airflow is 150mm void beneath the joists and sufficient airbricks, insulating between the joists have no bearing on this.
     
    stevie22 likes this.
  7. Maryfire12

    Maryfire12 New Member

    Thank you. So I’m not sure if this varies by area as I read some conflicting posts on this and had previously checked my local councils website on this and understood that no planning permission was required. We only replaced rotten joists in one existing room affected by damp, no extensions, no listed building, like for like replacement and although it was probably over 50% of the joists in that room, rest of ground floor area unaffected. We can’t change it now but I will definitely raise this with the builder.
     
  8. Abrickie

    Abrickie Screwfix Select

    Planning permission and building regulations are not the same thing. ;)
     
  9. stevie22

    stevie22 Screwfix Select

    You don't need planning permission (that's for extensions mainly). You do strictly need Building Regulation approval though many people wouldn't bother for this sort of thing.

    It's disappointing your builder didn't spell this out for you and/or ask you if you wanted floor insulation. You could have put in 50mm of Celotex and seen a substantial improvement though this would be less than required for strict code compliance
     
  10. Maryfire12

    Maryfire12 New Member

    Thank you for the clarification. Given I’ve not had the engineered flooring laid on top yet, my floorboards are still accessible. From what I understand, insulation for the floor should have been raised to me and insulation of the pipes should definitely have been done as part of laying new radiator pipes. I will therefore raise this.
    I think I’d prefer to look into another professional to install the floor insulation (my understanding is I could get someone to self certify if I get someone from the competent persons register). But if you have any tips please let me know.
     
  11. Maryfire12

    Maryfire12 New Member

    I received this response from my builder with regards to the pipe insulation. This seems like he’s fobbing me off. Can I double check is it correct to refer him to 4.24 of document L here? https://assets.publishing.service.g...attachment_data/file/1082462/ADL1_revised.pdf
     

    Attached Files:

    Last edited: Dec 22, 2022
  12. Abrickie

    Abrickie Screwfix Select

    No, it’s not a new system.
     
  13. dai.versity

    dai.versity Active Member

    A professional would have offered you the options, so that you both new what was required, and end up with a happy and successful job.

    Unprofessional are usually unsure how to do things and don't like details because thats what gets them into trouble, and they don't care whether you're happy or not, because they have loads of unhappy customers
     
  14. stevie22

    stevie22 Screwfix Select

    Within floor void I would take to mean enclosed and you have heated space each side so no energy is wasted.

    Under the ground floor you're heating the circulating air which is keeping the void dry (god for that, bad for your pocket)

    I think you've employed a smart #### cowboy who is trying to weasel out of putting his hands up.
     
  15. Maryfire12

    Maryfire12 New Member

    It’s a terraced house so the void is only the air circulating under the ground floor. I would like to refer him to the correct section of the document if possible. Is anyone familiar with what section states new piping in an existing system must be insulated? The builders installed new radiators and therefore new pipes in that room but the rest of the system remains unchanged. The closest would be 4.25: “In an existing system, when a boiler or hot water storage vessel is replaced, any accessible pipes in the dwelling should be insulated.” But I don’t think a radiator counts as a water storage vessel. Section 4.24 refers to a new system entirely.

    I would just like to be armed with the correct knowledge when I respond.
     
  16. dray

    dray Screwfix Select

    No offense intended, but are you pursuing this because you don't want to pay for the insulation because you feel it should have been included automatically within the job ? Although you might not agree with him ,seems to me that your builder has given his view, and evidence as to why he did not do it. Part L does not appear to apply so unless you specifically asked for him to include it , then it comes down to whether the builder should have anticipated you wanted it done, which is always going to be a minefield regarding right and wrong.
    These things are always difficult, but my view is that you are not going to win this one and perhaps you should try to see how you can reach agreement about the job and any extra payment due rather than guns blazing around the regs.
    Hope you get it sorted without too much falling out.
     
  17. Maryfire12

    Maryfire12 New Member

    It’s more of question of should it have been done or is it just the nice thing to do. Given where we are at in our renovation, I will likely go ahead and add some insulation to the pipes - either they’ll offer to do it or I’ll attempt to do it myself. I’m not going to push it. But what I do want to know is whether they should have done it (I.e it was a must) and is there evidence to back that up. If document L doesn’t apply as you’re suggesting, then it makes it seem that it’s all just a ‘nice to have’. Hopefully that makes sense? With the flooring insulation point, I can actually see clear evidence of that in document L. If he is trying to fob me off, I would rather just put the evidence on the table and let it be known.
     
  18. stevie22

    stevie22 Screwfix Select

    Were Building Control involved? If not then it's up to you what if any floor insulation you put in. What did you ask the builder to do? He's not going to give you floor insulation unless that's been agreed.

    As for the pipes I still maintain that to be good practice and I would expect it to be done. The document he produced refers to a floor void which I take to be enclosed by warm spaces where yours isn't. That's why I labelled him an SA.

    As Dray said I doubt you'll get anywhere arguing, but the good news is that DIY pipe insulation is one of the easiest tasks for a novice.
     
  19. dubsie

    dubsie Active Member

    Depends what's in the estimate, if he didn't agree to do it then the responsibility falls on you to get it done. Insulation isn't cheap, just GapoTape is 80 quid a roll so if your using PIR it will run into thousands to insulate.

    Me personally I'd go for a breathable membrane and then either sheep's wool or hemp followed by another membrane.....your still looking at a lot of money.

    So the reality is unless you builder has priced it up then he won't do it. I would have thought though he would have given you that option
     
  20. dai.versity

    dai.versity Active Member

    I think that is the nub of the problem - lack of communication - which may or may not be deliberate.

    But, also anyone carrying out repairs, just replaces to the same standard as the original before it was damaged. The only improvements would due to unavailability of original components
     

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