Low Tech Thermal Imaging

[cye]

Not having one of those thermal imaging cameras costing thousands.....

I recollect the days before loft insulation was commonplace. On frosty mornings, my late father would point out the roofs of neighbouring houses. "That one's had the fire lit", or "Those folks are away and the house is cold", or "That one with no frost anywhere has central heating", etc. The observations were more informative when several were made over the course of the morning, i.e., we could learn even more by watching how the frost melted over time.

Looking back on it now, whilst my father was a good neighbour, he was not was not at all a nosey or intrusive character - this was purely scientific observation, a poor man's thermal imaging. And entertainment too - The internet had not been invented and the test card was on the TV.

It is cold this morning. Still below zero and it's 10am.

Here's a pic of the back of our house (west facing), our's is the semi on the right hand side (RHS).

We have an old 1960s loft conversion which I've been insulating recently. The loft is open to the house (no hatch or door), so air can circulate to the loft room unimpeded. The fires have been lit on ours but not on our neighbour's (LHS). The neighbour has no loft room, but has an insulated loft floor and, I presume, a closed hatch.

Not a huge difference at this stage, but I am pleased that the tops of the knee/dwarf walls of the loft room are not visible, which means I've insulated the area where the knee walls meet the rafter insulation fairly well.

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[cye]

Here's a pic of the folks across the street. In all pics the roofs will face the same way, so that the solar radiation from the east does not muddy the waters.

On the RHS semi, which has a loft room, the tops of the knee walls are losing a little heat. Neither of the houses in this pic use their chimneys for fires, but are used for trickle ventilation.

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[cye]

and following on from the last pic, I am now panning to the left. There are 3 semis in this pic, the RHS semi in this pic is the LHS semi in the last pic.

The middle one looks fantastic. However, the house has just changed hands and the plumbers were there yesterday with the old radiators out on the street, so perhaps there is no heating.

Any other frosty roof pics from anyone?

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[cye]

and here's the back of our's at 11am.

top RH corner there's clearly something happening there, albeit above the loft room's insulation, which closes off 6" below the apex of the rafters. This is above the opening to the main stairwell and open to the rest of the house so possibly this is where most of the rising heat hits the 6" of polyiso rigid foam? Or it may be an indication of where the biggest airflow is above the rigid foam but under the roof tiles - There is a vent hole at the apex of the gable wall and this is where most of the air that flows on the upper side of the rigid foam will exit the building. we see a similar but weaker melt at the same point on the neighbour's semi to the left.

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[cye]

here's the neighbour's roof across the street again, also at 11am. this is the same house as that in pic2 (reply #1). note the considerable melt outside their loft room and along the entire ridge.

of course we cannot draw direct comparison between both houses as these will be heated differently. E.g., we run our's at 17c in most rooms whereas i suspect the house across the street operates at a conventional 21 or 22c, and so comparison of insulation between the two houses will be difficult as we have not maintained the 'scientific control'. A scientific control would have required us to keep everything the same, including heating, but varied and compared the insulation. To do this we would have needed identical heating systems in both houses with identical thermostat settings.

Comparison of different parts of one's own roof will probably be more useful.

Anyone any comments? Any pics of other roofs available?

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[cye]

and i've just noticed an ongoing problem with heat leakage from the kitchen roof. that's the little annex roof below the wall-mounted tv ariel.

i broke into this closed space a few year's ago to insulate the kitchen ceiling, and discovered that the plumber who installed the gas boiler in 2000, employed by the previous occupants of the house, had been in somewhat of a hurry and had taken a few shortcuts. The bodger had passed the 28mm flow and return pipes for the boiler up through the kitchen ceiling and through this void but had not insulated them. the pipes were effectively, whilst under the roofing tiles, in outside air. Not being satisfied with just one shortcut, to take the pipes into the bathroom, he had broken a hole in the back wall of the house, directly below the TV ariel but between the kitchen roof tiles and the kitchen ceiling. This hole, the size of the average tv, being under the bath and invisible to his unsuspecting client, was left open. A huge hole with two pipes passing through it. This discovery explained why the towels flapped around on the towel rail on gusty days. Gordon the bodging plumber was clearly proud of his shortcuts as he signed the brickwork beside the gaping hole.

I insulated the pipes and closed the hole through which the pipes pass with plugs of glass fibre insulation. I also laid 200mm of fibre quilt on the kitchen ceiling, thinking I'd dealt with the problem for good.

I now realise i should have used expanding foam to close the hole instead of insulating quilt, because warm air is clearly still filtering through to the roof void.

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