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I’m currently working on plans and costings for converting an old stone building into a two-bedroom cottage. It has 2 foot thick stone walls and will need a complete new roof (it’s currently a shell with a dodgy slated roof that may be falling in as I type!). The building will be on two levels and will have bedrooms in the loft area.
BTW this is my first build so I’m kind of feeling my way in the dark just now!
Roofing I basically want to make the building as insulated as possible and use as minimal heating as I can get away with. I’ve investigated SIP roof structures, but does anyone have any real life experience of the insulation properties of this compared to conventional roof? And any other experience on installation, cost, etc?
Heating I had thought originally of using underfloor heating under engineered wood floor throughout, but would this be suited to upstairs too? Also, since the building will be fairly compact and hopefully well insulated, then am I better off trying to heating the whole volume of the house? i.e. standard central heating.
And if I have underfloor heating throughout what is the best option for water heating? I would like to fit a couple of solar panels on the roof so could this link directly to a simple electric heater? Note: there will be a sink in the kitchen, sink in the bathroom and a shower…and that’s it.
I will no doubt have dozens more questions as I go on, but these are some of the biggies that I need to decide on.
Prop the roof as a matter of urgency. I don't know what your location is, but if you are left with a roofless shell you may have problems with the planners, especially if you are in the green belt or open countryside. It doesn't matter if you end up replacing the entire roof once you have permission, but it's a hell of a lot easier in planning terms if you still have something there to begin with. I am being seriously stitched up with a similar situation at the moment (even though I was told by the planners that I could repair the roof before I bought it) If you need any more advice you can whisper me.
For a really well-insulated two bedroom cottage I doubt you'd need any heating upstairs. Woodburning stove plus backboiler and solar panels is an appealling combination for a rural area, maybe backed up by an electric immersion heater for emergencies. I know people who have a woodburner connected to underfloor heating, and they are very happy with that, but in a very small house I don't think I'd bother with the UFH myself. Underfloor insulation would be good, and external insulation of the walls would be wonderful if you can do it. Triple glazing? Internal insulated shutters instead of curtains, taking advantage of the deep reveals you thick walls will give you, so that the shutters fold flat against the reveals in the daytime? I live in a small stone cottage - the above is pretty much a list of what I'd do given the budget and if the National park would let me...
Dominic, thanks for the advice, but I may have exaggerated a wee bit. There is a dormer window that is caving in, but I think the bulk of the roof will last until I get a planning app through and start an upgrade. I've attached a pic to give a better idea of the building.
I can't really insulate any walls externally as its all nice sandstone and its also grade C listed (in Scotland). So all insulation will be inside. Good point on the triple glazing...it will need all new sash and case windows so I'll make a point of ensuring these are triple glazed. Can you get triple glazed velux type roof windows too? I'll look into the insulated shutters. Nice idea. Any links?
In terms of heating, I wasn't convinced about having a stove as a single source of heat. Just for the hassle factor when you want instant heat, say for only an hour or two. Maybe a stove backed up by electric UFH downstairs would be a good mix though. For water, solar panels plus electric immersion sounds good. Are there any off-the-shelf combinations that do this? I guess it can be quite a small tank given that there will be no bath (electric shower only) and its only 2 bedroom.
Anyone have thoughts on SIP for the roof?
What sort of total thickness should I allow for the roof for my draft plans (currently checking out headroom in the loft space)?
No links for the insulated shutters I'm afraid - it's just an idea at the moment. But I had in mind Kingspan (or similar) with 4mm ply both sides and a wooden edging, hinged onto a wooden upright each side of the window, with draughtproofing strip appropriately placed around the edges to form a reasonable seal when shut.
Here's neelpeel's image reduced to 600x450 pixels to fit in the forum software's apparent limit of 600 pixel width. I suspect from the file name that neelpeel tried to reduce the image size but something went wrong.
if you are having solar panels then an electrric shower is not the way to go.
I would aim for a stove with back boiler, and solar going into a thermal store (size dependant on heatloss calcs) from which you can supply your DHW and UFH.
All that "nice sandstone" would serve you a lot better internally as thermal mass than externally as aesthetic pleasure.... oh well listings eh?
Regarding old stone buildings, some would say that it is a modern fashion to have exposed stone walls. The traditional way, and certainly with our place and in the area, they lime washed the walls externally as standard. That being the case, surely there is an argument for externally insulating and then rendering with lime. This would be more in keeping with the original look, not to mention the functioning of the building as designed by the original builders???
It is frustrating being forbidden to externally insulate a house, in the knowledge that had the materials been available to the original builders, they would certainly have done the same.
I agree with your points, however, most of the buildings in the village have exposed stone and I'm pretty certain that the planners would have a hairy fit if I wanted to insulate externally. They did at least have no issues with me adding windows on the South side, pointing out that the solar gain would help with heating. Ndon, I see your point on the shower. I've actually been doing looking through the forum and I think I've got a fair bit of reading to do before I decide what to do about heating.
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