I'm looking at upgrading the insulation in our 1960s bungalow. Could you give some details on what you focused on Micks'r?And to put in perspective what I'm getting at, I live in a deep retrofitted 1970's bungalow
First off, while insulation is important, it's not the be-all and end-all its often made out to be. Very often too much emphasis on insulation and not enough (or none) on airtightness and ventilation.I'm looking at upgrading the insulation in our 1960s bungalow. Could you give some details on what you focused on Micks'r?
I was the advisor. (I'm an engineer who has specialised in domestic heat loss mechanisms and solutions)I agree with everything you have said and the detailing you mentioned. Would you care to name your advisor for that build?
Few questions if you wouldn't mind, maybe we need a separate thread but sounds like a great project!First off, while insulation is important, it's not the be-all and end-all its often made out to be. Very often too much emphasis on insulation and not enough (or none) on airtightness and ventilation.
So, you need to understand first the 3 forms of heat transfer (loss) i.e. conduction, convection and radiation and address each one with insulation, air tight measures and glazing options respectively. Also, as you add insulation the role and impact of thermal bridging (relatively high conductive material bridging your insulation layer) becomes very significant not only for heat loss but also potential for mould growth internally. Finally, you need to ensure sufficient ventilation is provided to exhaust the internally generated moisture from normal occupant activities.
So, what we did was
1. Tested the house for air tightness to understand all the air tight issues (>10 m3/hr/m2@50Pa). The weaknesses then were addressed in a methodical way and incorporated into any other improvements - basically all junctions and penetrations of the external thermal envelope were air tightened using a variety of air tight materials. Final test show huge reduction to less than 1 m3/hr/m2@50Pa, >90% improvement!
2. Whole house mvhr system installed in the attic space
3. 300mm cellulose pumped into the attic
4. 200mm rockwool ewi extending down 600mm below the finished floor and up past the soffit to meet the attic insulation. By going down past the floor and up past the soffit, the linear thermal bridges were pretty much eliminated and also the need to insulate the original concrete floor slab was mitigated (personally, I prefer a slightly cooler floor slab under my feet when everything else in the space is warm, ... I don't like underfloor heating for this reason). We went with 200mm ewi for 2 reasons: 1. we had a 450mm soffit so 200mm still left a 250mm soffit and 2. doubling the insulation thickness added only about 10% to the ewi cost.
5. Replaced all windows the ph certified units and installed them flush with the external wall outer surface so that the ewi overlapped the thermally broken frames, again eliminating the thermal bridges around the opes.
1. Yes, blower door used. With the correct weather conditions, a thermal imaging camera, trace smoker and, most importantly, an experienced surveyor/tester all major weaknesses are readily identifiable. As I do these surveys for a living, this was the easy partFew questions if you wouldn't mind, maybe we need a separate thread but sounds like a great project!
- 1. Once you got the house tested for airtightness (which I understand is a blower test), how did you go about identifying weaknesses in order to address them? I haven't come across anyone who provides such a service or even a decent guide of how to go about it.
- 2. How did you continue your EWI above the soffit?
- 3. Could you name a supplier for passive house certified windows - what sort of a difference (performance & price) would you be talking Vs SEAI approved double / triple glazed windows?
- 4. Can you explain your window detail more? You moved the windows all the way forward to they're flush with the outer edge of the insulation? How did you install the windows in that case? Or you insulated over the window frames once they were installed?
Thanks for that, re: no.4, would installing the windows in their old position, prior to the ewi, not have an end result of more insulation over the window frames in any case? The ewi installers would hardly have left the frames bare in either position?
By not moving the windows out you are left with a significant thermal bridge, the consequence of which is a real risk of mould formation internally on the reveal.Thanks for that, re: no.4, would installing the windows in their old position, prior to the ewi, not have an end result of more insulation over the window frames in any case? The ewi installers would hardly have left the frames bare in either position?
House is 1920s, 2 storey end of terrace, suspended wooden floors in hall & reception rooms, solid floor in return (not insulated at ground level), no insulation apart from some DIY rockwool in attic, red brick so EWI solution not an option.
Apologies, meant to say Passive House standardI'm not 100% sure what you mean re build passive for the extension - the extension is largely half of an open plan kitchen/utility area, the other half being one of the current reception rooms.
That's a great document, thank you for the link Leo. Though I just find it hard to actually believe that adding 100mm external insulation to 2 ft thick stone walls is actually going to do any good on a "Type 1" house like ours...Take a look at this guide, it provides decent guidance on what should be tackled first in terms of return on investment for a lot of the common Irish house types.
I've talked with with a well versed conservation joiner on this who is in and out of many building like this. You've to be very careful when dry lining or insulating stone walls. The walls are designed to breathe so need to do so or damp and mould issues can result.That's a great document, thank you for the link Leo. Though I just find it hard to actually believe that adding 100mm external insulation to 2 ft thick stone walls is actually going to do any good on a "Type 1" house like ours...
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