1er Heat Accumulation floor house in summer - solutions?

[ojal]

Hello,

I live in a two storey house with an open central staircase. The house is equipped with electric and the insulation corresponds to what was done to its construction for a house heated in electric in the 1980 years. It is lined with gypsum plasterboard with a thickness of polystyrene insulation. The double glazing is a double glazing basic of the time. The attics are said lost, the insulation is placed on the ceiling plates and no insulation is present under the tiles.
In winter, everything is fine, no feeling of cold, but it is the comfort of summer which is to improve. Indeed, if the RdC remains correct, it is not the same floor and especially the office room of a dozen m2 in which we work with my wife.
We did strengthen the insulation of the attic there is 3 years, but we did not feel any difference in summer comfort ... I assumed - wrongly? - that the very warm air of the attic radiated on the parts of the floor ... Our problem is especially at the end of summer day when we ventilated the rooms during the freshness of the night and that the temperature rises progressively to the thread of the day ...
I was wondering if ventilating the attic to extract the super hot air that accumulates in the attic would bring comfort, but I doubt that with the thickness of insulation that we currently have, this hot air can cross the thickness of the insulation ...?
Do you have any food for thought or solutions as this problem should be a problem are all very conventional?

Thank you in advance for your answers

[Did67]

I think there is a classic thermal inertia problem. A lack of heavy "materials" capable of storing the calories that go in despite. The more you insulate (from the inside), the less "masses" you will have and the more calories that pass anyway (especially through the roof windows) will cause overheating.

Radiation effects can be added, which "pass through" the insulation.

I do not know what are the possibilities to add thermal inertia: interior brick walls? to double bulkheads with heavy materials, able to store calories?

Or if the exterior walls are "massive" (stone, concrete, bricks), insulate from the outside, so that this "mass" is located inside the insulating envelope, and not on the outside. outside...

[Gaston]

If it is a room where you work, are there sources of heat related to this work (lighting, computer, machine, ...)?

In this case, the insulation can also work against you by preventing the heat released from escaping.

One solution could be to organize an air circulation with a room of a lower floor

[Obamot]

I was wondering if ventilating the attic to extract the super hot air that accumulates in the attic would bring comfort, but I doubt that with the thickness of insulation that we currently have, this hot air can cross the thickness of the insulation ...?

To make it short, it seems that currently you have a thermal bridge that acts as a heat accumulator (wall of facade):

- you do not give the thickness of polystyrene insulation, but to read you, it would have been placed inside the habitat between the placo and the wall (so it's an ITI.) It should not do more than 2 inches.
- you do not give the thickness or the types of insulation in under-roofing, nor do we know how they were laid (photos would help, especially the areas of jointing between insulation and against the structure.)
- the effectiveness of an insulation is measured by the magnitude of eXergie obtained AFTER insulation and finishes. Which means that relative to thermal inertia, it is the weakest link which determines the performance of the assembly.

I deduce that if the foregoing is correct, there seems to be no continuity between the insulation of the roof and the walls (the walls of the attic are not in this case not isolated, nor of the interior, nor of outside). Your walls thus act - from top to bottom - like piles accumulating heat, and by convection, it accumulates under the roof, which means that as Gaston suggested, insulation works against you, since it allows you to accumulate heat under insulation!

It's easy to check in the summer and in the morning as soon as the Sun is typing, with a laser / infrared thermometer (by making temperature readings on the walls and in particular on the inside of the walls of attics exposed to the Sun, and this early before it has accumulated, or even by putting your hand against the wall every quarter of an hour since sunrise, noting the differences as the heat builds up. inside / outside.) The wall must be progressively warmer, even before the heat has accumulated in the attic (it seems to me that this would be a good indicator to understand the principle.) At first, if this hypothesis is correct, the wall should be hot outside, and warmer inside (in the attic).

In a case like this, the only solution is the insulation from the outside of the facade walls (ITE to ensure the continuity of the roof insulation). And there - if it was sealed (but not waterproof) - your power consumption should drop to 2 or 3 tenth of your current average bill.

Provided you do not have a metal frame.

[izentrop]

Hello,
Exterior blinds for windows in the south to prevent solar heat gain.

[Did67]

I add to what I wrote and that was written (indeed, blinds external, indeed, if computers, we must evacuate their heat!):

1) if the attic is not used at all, then indeed, maximize the insulation both against conduction (glass wool or better, wood wool) AND anti-radiation screen (reflective fabric). The roof is often, in summer, an iron over the head (touching tiles in summer!).

2) We can, in fact, "deport" inertia by circulating the air; it is the principle of the "Provençal well" (or Canadian). But if you have a cellar, a hard barn or whatever, you can use it to cool down by "importing" the cooler air. Prafois odor problems and / or dust, mold or spiders: this can be managed through a type VMC DF exchanger (double-flow).

[Flytox]

In the old family house, not very insulated (about 15 cm of glass wool out of age on the ceiling) this problem of the unpleasantly too hot ceiling in the summer was significantly reduced by opening wide the 2 access hatches to the attic. convertible. This creates an "important" circulation / suction of air and the temperature drops (about 2 ° C?) For the night. We open around 19:00 p.m. and close when we go to bed.

We tried to increase the phenomenon by adding a fan in the hatch, which sucks in the house and rejects in the attic. It may work better ... but there is noise and more ....

[ojal]

Thank you for your answers

Hello,
Exterior blinds for windows in the south to prevent solar heat gain.

By closing the shutters, the problem is the same

If it is a room where you work, are there sources of heat related to this work (lighting, computer, machine, ...)?

Yes indeed, in the office we have sources of heat, but even without these sources the problem exists; For example if we miss a day without there is a source of heat, overheating is present ...

In this case, the insulation can also work against you by preventing the heat released from escaping.

Yes, I also thought about it, but in the case of the ceiling, in summer, it will be always warmer in the attic than on the first floor ... So we need a strong insulation on the ceiling ... Difficult also to reduce the insulation of the walls

One solution could be to organize an air circulation with a room of a lower floor

Not easy to set up, but to think about ...

How would I know if the attics that must be often very hot (more than 50 ° C ???) do not bring heat to the floor, despite the insulation that has been reinforced - I think we has added on the old rock wool about thirty cm of wool (I do not know what, a product projected as white cotton wool). If necessary, a forced ventilation of the attic should lower their temperature and can be improved the comfort of the floor ???

[ojal]

- you do not give the thickness or the types of insulation in under-roofing, nor do we know how they were laid (photos would help, especially the areas of jointing between insulation and against the structure.)

The attics are not insulated, the insulation is projected on the plasterboard ceilings of the floor and this insulation is without breaking over the entire surface of the house in the inner periphery of the spinal cord.
The interior insulation of the walls comes below the ceiling insulation and therefore at this level there is no thermal bridge ...
The facades accumulate heat, it feels very well in the late evening or outside we feel very well the radiation emitted especially on the south and west faces ...

In the winter, I can measure colder zones and thus thermal bridges with a thermal bridge, but in summer, all the walls are at the same temperature and I can not visualize any thermal bridges. .. In summer, temperature differences are not as important as in winter ...

I can not for the moment consider an insulation by the outside, nor to modify the insulation of the walls ...

The tracks that I have to ventilate the attic to lower the temperature since it must go up very high, but is it useful ???

[izentrop]

Thank you for your answers

Hello,
Exterior blinds for windows in the south to prevent solar heat gain.

By closing the shutters, the problem is the same

If the shutters are very hot and at the same time the windows are open, the heat comes in anyway.

I was talking about outdoor venetian blinds for example, which let in the light but not the heat.