1st floor extension options?

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  • 1st floor extension options?
  • qwerty
    Member

    Thoughts?

    What are the footings like?

    sc-xc
    Member

    ^ my first thought was about the foundations.

    I always understood double storey extensions needed deeper/different foundations?

    Rockhopper
    Member

    You need to get a structural engineer to do the calcs to keep building control happy – a lot will depend on the footings your current kitchen is built on. You may well have to expose them to do the loading calcs.
    I’ve done lightweight construction before but it still needs to be designed correctly.

    As to the timber cladding idea – well you’ll have to judge how that would look (pretty rubbish in my opinion, it’ll look like a cheap add on rather than an improvement to your home). The planing department at the council will have their own thoughts as well 🙂

    sc-xc
    Member

    The planing department at the council

    At least they will make sure there are no jaggedy edges 🙂

    UrbanHiker
    Member

    Yea agreed on the look of timber cladding. Wouldn’t be my 1st choice, but does seem to be the cheapest. Could it be clad in say some sort of vertical tiles, that might look better.

    Not sure about the footings. They were all dug out and put in about 10years ago, but only for a single storey. I do have architect drawings for them, would that be good enough to go from?

    When you say “expose” the footing, how much of a job is that?

    Rockhopper
    Member

    Well spotted 🙂

    Rockhopper
    Member

    You’ll just have to dig down until you get to the bottom of whatever is there, really to confirm how deep they are and what the ground conditions are like. I would guess that the original extension was built with footing to suit a single story building, they wouldn’t over build them unless you asked them to.
    Find a structural engineer and let him have a look at your original drawings. There is bound to be one on here I would have thought.

    UrbanHiker
    Member

    I might be remembering it wrong, or the original builder could have been feeding me a line, but I remember him saying that the footings for single or double storey would be identical. I’m assuming, from the above comments, that is not the case?

    jtintheuk
    Member

    You could still go with a lightweight timber construction and clad with a brick slip system.

    marcus7
    Member

    I’ve just had to do this ( changing a single to a two story), digging out proves to your structural engineer that the footing will support the extra weight. ours were a little over 1m and they like to see the bottom!. it’s a plain to dig especially if you have restrictions on access. we were lucky as the footings were made to be two story and don’t need underpinning. a structural engineer will tell you where he wants the hole and building control will want to see the calculations, it cost us over £1500 for this alone, although there were other calculations needed for the other side of the house which are a lot more complex.

    UrbanHiker
    Member

    Hi all,

    I’ve currently got a single storey kitchen and bathroom, measuring about 4m by 10m, built to building regs of about 10yrs ago.

    I’m looking to have a 1st floor extension added above about a 1/4 it (2.5m by 2.5m) for an additional bathroom.

    Just wondering what the construction options are. There is no steel support in the current flat roof, so I always assumed the thing to do would be to add a couple and build in block work. But had a builder look recently and he seem to think that he could build in timber, with timber cladding, on the current roof with no steel.

    Does that sound reasonable? He’s quoted under £4k, which to me sounds about 1/2 what I though it might cost.

    Thoughts?

    Rockhopper
    Member

    Brick slips are certainly an option – only ever done that once and everyone was very nervous about how well they would stick on!

    The footings may well be fine for a two story extension but building control will need you to prove it. They wouldn’t necessarily be the same footings though as a two story extension is a lot heavier than a single story one (not quite twice as heavy because of the roof)and if a builder can get away with using less concrete than he has to then he will (the same as a client would like to save a few quid if he can!)

    UrbanHiker
    Member

    Nice one thank all.

    So aside from looks of the cladding, are there any other downsides to timber frame?

    Indeed, would it be worth (and why) going for a traditional double skin brick built one?

    marcus
    Member

    You could always look at the helium filled cavity wall option if the ground floor construction / existing fondations dont look uo to the job

    wrightyson
    Member

    I would suggest any decent builder within the last ten years would have dug founds to take a storey above. Depth of excavation is key, not depth of concrete within the excavation. Dig out (pardon the pun) the old plans if available, also building control may have records of the original inspection.

    Premier Icon paladin
    Subscriber

    I recently built a 2nd story over a 1960’s flat roof extension, didn’t have to inspect the founds, so building control must have been satisfied with original plans.
    Timber frame construction cos that’s how its done up here 😀

    antigee
    Member

    I might be remembering it wrong, or the original builder could have been feeding me a line, but I remember him saying that the footings for single or double storey would be identical. I’m assuming, from the above comments, that is not the case?

    not sure when building regs changed or may be remembering wrongly but my understanding is current building regs would require footings to suit double storey if a single storey extension on a two storey building with assumption might get built on – so if you have signed off building regs from 10 years ago he may well be right

    edit and I’d ask myself if a timber/clad suits current building – that is does it detract value rather than add? would spending more give better return on selling?

    My gut reaction is get the ideas of what is possible / economical (in the if we did this you lose X but save Y or we do this and you get this but it costs)from the builder and then get a drawing service to do a plan – unlike architects many work for a fixed price and will probably answer your building regs question – once you’ve got the plan the builder can show you what they’d change to make it work and you can agree who is responsible for what exactly

    tymbian
    Member

    Timber cladding won’t necessary look bad and can look right if tastefully done even if you only part clad. You could use a cedar or something like a Scotlarch ( locally sourced and sustainably managed ) or a Siberian Larch.

    Timber is a sustainable product and IMO should always be the first thing to consider when building. We have more forests in Europe now than we did 100 years ago.

    antigee
    Member

    Timber cladding won’t necessary look bad and can look right if tastefully done

    I agree just think it important especially if on top of existing extension that the look fits rather than looks like a messy addition

    Premier Icon footflaps
    Subscriber

    I might be remembering it wrong, or the original builder could have been feeding me a line, but I remember him saying that the footings for single or double storey would be identical. I’m assuming, from the above comments, that is not the case?

    No, double storey brick has deeper footings. The actual figure depends on the local ground conditions (soil type) and/or nearby trees eg if you happen to be next to a Eucalyptus tree they might specify much deeper footings as they are very thirsty trees.

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