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Retiling roof and adding/replacing existing velux

Discussion in 'Floors, Stairs and Lofts' started by drpepe, 22 Feb 2018.

  1. drpepe

    drpepe

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    Hi

    We have a Victorian terrace with a mid-90s loft conversion (so no idea of the spec in areas I can't access) - it has proper stairs, a bedroom & an ensuite in a small rear dormer. The loft was regularised by the council in 2013 as part of our purchase of the house.

    It is not really very useful as a bedroom as is drafty and roof is also a bit leaky, so currently being used for storage.

    We need to get the roof fixed, and the roofer we spoke to identified a list of other problems or irregularities e.g. non breathable felt (we have several tile vents), bodged velux flashing, repoint chimney etc, that would be good to do whilst he's up there. The re-felt and re-tile, sort velux flashing, and several little jobs for about £5k.

    Questions

    1. How interested would building regs be in this work? what about if we wanted to replace the velux with a bigger one or an additional one?

    2. Would I have to bring the insulation up to modern standards if the roof was retiled? Would the answer be the same if we also added the new velux?

    3. I have a feeling there wouldn't be enough headroom for more insulation as the ceiling is currently max 210cm (in a 30cm strip along the apex, the rest is sloping) and the rafters are just 2x4 inch what would the options be if this was the case?

    Any comments appreciated :)
     
  2. Tony Bolger

    Tony Bolger

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    5k sounds a bit much for a Victorian terraced restate.
    However, as I understand it, and I’m no expert, if it’s a re-slate building control will want the insulation upgrading further, bitumen felt isn’t a problem provided there is a 50mm are gap between insulation and felt and slate vents, but if it’s being reslated and new battens etc, a breathable membrane could be used and no need for slate vents, assuming you have the air gap.

    Converting to a warm roof from, I’m guessing your cold roof would be tricky in a mid terrace so additional insulation may need to be done from the inside, not ideal for you.

    You may need to speak to building control or at the very least get a full spec off the roofer to show compliance with regs, the bigger Velux would not be a problem on the back, under permitted development rights, if on the front it may need planning permission, maybe.
     
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  4. drpepe

    drpepe

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    Thanks for your comments.

    I'm not sure the difference between cold/warm roof construction, but interesting comment about not needing the tile vents if breathable felt is used. Is this still the case if our house doesn't have soffits (see below)?

    Also if there's no requirement for a 50mm ventilation gap below the felt, that presumably means we'll be able to fit ~50mm more insulation in there between our meagre 2x4 rafters?


    The estimate of the work was 4500-5000. This includes the refelt/retile, recladding our small dormer and replacing flashing on 3 velux
     
  5. Tony Bolger

    Tony Bolger

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    Hi, warm roof = insulation on top of the rafters which is then tiled etc but it means raising the height of your roof by about 6in, not really feasible in a mid terrace house, and Planners are not keen.

    Cold roof = insulation between and under the rafters. Roof height stays the same and the planners prefer it.

    Building control are not bothered either way so long as you achieve the desired u value.

    Building control will probably insist the insulation is improved if more than 25% of the roof is being retired.

    The breathable membrane does not need tile vents or soffits because the entire roof can breath, but it still needs an air gap of (I think) 50mm.

    I’ve not priced up any roofing jobs for 17 years but scaffolding, skip, materials and labour for 2 men for a few days could, I suppose, come to 5k depending on your location.

    You need to know exactly what insulation you already have but some of the new multi foil space blanket stuff may get you up to the required u value (when used in conjunction with your existing insulation, depending what you have) though not all building control jurisdictions allow it, if they will accept it, you MAY get away with not having to disturb the interior at all.

    The regs regarding headroom only relate to the staircase which can be as low as 1.9m , no minimum headroom requirements for the room itself, just thought I’d mention it in case you end up having to reduce the ceiling height, but you probably knew that anyway.

    I am probably going to need something like a ridgelight above the top of our staircase to comply with headroom regs and a mist system to keep everything open plan.

    Building control mainly seem concerned with insulation, fire protection and structural integrity confirmed by SE calculations.

    Planners are only concerned with how it looks from outside.

    I assume building control are involved, or will be ?
     
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  7. drpepe

    drpepe

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    BC were involved in the regularisation 3 years ago - they passed the insulation, structure, fire measure. Based on the planning portal statement below I didn't think i would need BC involvement just to reroof (modifying the insulation & extra windows would happen separately).

    Current insulation is kingspan type board, but it appears quite loose and gappy (from what i can see in the eaves). The eave storage isn't insulated properly either. Add in the roof tiles and it is very draughty.

     
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