insulating a loft when joists are already boarded over

12 Jun 2016
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United Kingdom
I live in a tiny stone and slate cottage, and currently have no loft insulation. The loft floor has been boarded over with tongue and groove, bonded to the plaster board ceilings below. Removing the flooring would destroy the ceiling, which has old oak beams.

The old insulation was removed to treat the floor for woodworm, and as I have been heating the cottage with a stove, I haven't worried about replacing it as there are no savings to be made. However, I am about to replace the stove with electric heating, and so need to think again about loft insulation. Is it just a matter of rolling out 270mm on top of the boards, or is it more complicated than that?
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Basically yes, but make sure you don't block the loft ventilation from under the eaves.

You do realise that using electricity for heating is very expensive don't you, about two to three times the cost of gas.
if only ..............I've lived here over 25 years and never a word about bringing mains gas to these godforsaken parts - my multi fuel stove has always been enough to warm my little space, but the dust and dirt and lugging of coal and hot ash about, not to mention time spent on ageing knees, are all getting too much for me - last straw was getting a digital carbon monoxide alarm and realising I had to leave back door open for 30 minutes or so after cleaning out ash to bring reading down to 0
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Make sure you lap over the edges of the ceilings over the external walls but, as mentioned above, allow the flow of ventilation in to the loft space via the eaves ( edge of roof). If the insulation is shy of the external walls it will cause black spots on the underside of the ceiling ( thermal bridging) .

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