I’m buying a 1960s property. Is it worth getting roof and floor insulation?
Q: We are interested in buying a chalet-type property built in the 1960s. I am worried that it could be very hot in the summer and very cold in the winter. The Energy Performance Certificate gives it a D59 Energy Efficiency rating and recommends room-in-roof and floor insulation. How effective are these in controlling heat variations?
According to the property’s Energy Performance Certificate, it seems that there might be some insulation in the roof, however it is also recommending that the roof needs more insulation.
EPCs aren’t always perfect and it is possible that there is adequate insulation up there, however it is equally possible that there isn’t and the previous owners simply put up with high heating bills in winter and overheating in summer.
Typically in a roof room, you’ll have anything up to five different surfaces that need insulating.
Firstly, there’s the flat roof (if present) in the centre of the room, then there’s the slope (where you can insulate between the rafters), then there are the stud walls (which usually enclose storage space which will typically be uninsulated) and finally there is the portion of flat roof (known as the residual) which is above the room below.
In an ideal world, all of these surfaces should be insulated to provide a thermal barrier which fully encloses the room. In practice, one or other of these may prove challenging or expensive to insulate.
Your first step should be to try and work out to what extent the room is already insulated by looking behind any access hatches that exist.
There may be a hatch up to the flat portion of the roof and you may be able to access the residual loft space through storage doors in the stud wall where you will be able to see if there is any insulation on the horizontal part. You may also be able to see insulation up in the rafters.
Alternatively, call a local insulation installer and ask them to assess the current level of insulation and make recommendations. Check the National Insulation Association website for local installers.
The work could be quite disruptive. However, if there is minimal insulation up there is will probably worth your while improving it, both from a financial and comfort perspective.
Badly insulated roofs can leak enormous amounts of heat in the winter and can get very hot in summer as the sun heats the roof tiles and these radiate heat into the rooms.
Floor insulation can also be worth doing, however it would be likely to have a more modest impact on both bills and comfort.
It is very likely that the EPC is correct in stating that there is no floor insulation present as it is a relatively unusual retrofit measure and wouldn’t have been included as part of the original build. Again, an installer will be able to advise on the potential for this measure and costs.
Finally, a measure which doesn’t feature much in the EPC but is a cost effective way of reducing your heating bills and greatly improving your comfort is draught-proofing.
Spending the time on a windy day to find out where the draughts in your home come from is well worth it and rectifying many types of draught can be a quite straightforward DIY task.
Answered by Dr Paula Owen, Green Gumption Eco Sustainability Agency
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