HQE House Project in the North

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.az.
I discovered econologic
I discovered econologic
posts: 3
Registration: 11/05/09, 13:31

HQE House Project in the North




by .az. » 11/05/09, 14:16

Hello,

Currently an intern in a building company, the boss has decided to embark on the adventure of HQE, and here I am in charge of the file. After describing an environmental policy and the level of targets, we set a very high level in the low impact of the site, the control of water and energy.

However, the "leader" does not aim for a high performance target 2 (Integrated choice of construction processes and products). Or rather, it will never be possible. :?
If I understood correctly, he wants to make wooden walls and pour concrete in the middle void, while insulating from the outside. So we would have from outside to inside:
wood / insulator / concrete / wood.

When we see the gray energy spent on the production of cement, I find that there is nothing HQE in there. To overcome this problem, I proposed a straw frame with lime / clay coating, but I found myself with a quick and definitive no. Now, I'm not sure what to turn to, knowing that he really wants to have a wood exterior with good thermal and sound insulation.

This is why I defer to you in order to guide me on the possible choices.
Including wool (eg: hemp) between the "lintels" is unacceptable (risk of fire), cork is too expensive, and glass / rock wool would have a negative impact with the production of dust and lower RT over time.

If you had some econological ideas that I can submit to him, I would be very grateful to you, because not being a professional in the field and having a limited knowledge, I have been looking for nearly a month for a viable solution, but nothing seems to be suitable .
Thank you in advance for your answers.

PS: I will keep you informed of the continuation of the events, hoping that everyone can benefit from my experience.
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aerialcastor
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Registration: 10/05/09, 16:39
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by aerialcastor » 11/05/09, 14:56

Hello,

At first glance it looks not so bad .... you would have to tell us a little more:
Is it for a house, a building?
Is it possible to have solar gain?
In which region is this?
What thickness and what type of insulation is provided?


Certainly concrete is not the most ecological but it allows a very high inertia which allows to store solar gains and to smooth temperature variations.
But it is not perspiring, alas .... see if you can not have instead a lime concrete or bricks of raw earth (but there the budget will fly). This is only valid if the insulation is obviously breathable.
Increasing the thickness of the insulation is always beneficial (unless the "chef" has already provided 25cm but that would surprise me).

Do not focus on the gray energy of the materials, it does not weigh heavy compared to the energy necessary for the operation of the building (heating, air conditioning, lighting) if it is poorly designed. So first a good design. Materials with low environmental impact are the icing on the cake.

People are too likely to think that an ecological house is a standard house which is replaced by concrete block by wood and glass wool by hemp, while it remains an energy sinkhole. I repeat myself first a good design (it does not cost much more) then after if there is still a budget for low impact materials.
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.az.
I discovered econologic
I discovered econologic
posts: 3
Registration: 11/05/09, 13:31




by .az. » 11/05/09, 15:25

First of all, thank you for this quick response.

Then the site analysis (in the North (59), 15 km from the sea, shows good sunshine and significant wind potential. In addition, having a chalky base, geothermal energy will find all its appeal. , there will therefore be geothermal + wind (for the moment, solar does not seem to be one of the priorities).

The future house will consist of a ground floor + upper floor, enjoying maximum sunshine with openings to the south in order to take advantage of passive solar energy.
Being in a building company, efforts have already been made in terms of insulation (eg breaking thermal bridges) and seem to be fairly well acquired. Only, on this project, the "chef" wants to work with a glued laminated wood siding, but I do not know more about the type of insulation, nor the thickness. I look forward to a meeting to find out more. The only thing known is that there will be exterior insulation at the walls, but also insulation at the foundation level, in order to keep the calories from geothermal energy.
The roof will consist of a tank (galvanized?) Suitable for the recovery of rainwater. a green roof could possibly be considered (note the double conditional :? )

Thanks to your answer, my received idea on concrete is modified, because in addition to having a buffering capacity for the diffusion of heat, it seems to have a good thermal and acoustic capacity, but the hygrometric comfort in the house does not risk it not to be seen on the downside?
I think there will be the use of a double-flow VMC, but again my knowledge of air quality is insufficient. However, the interior temperature should be fairly well controlled in order to be well below RT 2005. It seems to me that an additional heating with wood (pellets) will be included for ideal thermal comfort in winter.

But still speaking of insulation, which would be advisable for wood cladding? (by the way I will ask which species will be used)
Is a wood / insulating / concrete / wood wall really a good idea?

Again thank you for these answers which help me to see more clearly in the econological approach.

PS: sorry not to say more about the location, but being in training, I'm afraid that my approach on this forum could be misinterpreted and be discriminating during my final grade. I prefer to use the precautionary principle ^^
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aerialcastor
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by aerialcastor » 12/05/09, 22:50

Hi,

I do not really know the climate of the North but since it is near the sea, I imagine that it is quite temperate, not too hot in summer, not too hot in winter.
And there with good insulation from the outside, good inertia and good management of solar gains, we must be able to do without central heating.
So geothermal energy (which I think is more of a ground / air cap) + the double-flow VMC does a lot. I will abandon the cap and will put the € 15000 that it will cost in insulation.
The double-flow VMC which finds its interest rather in harsh climates, has the merit of distributing the heat evenly. I think it also manages the humidity but to be verified.
If I understood correctly, he wants to make wooden walls and pour concrete in the middle void, while insulating from the outside. So we would have from outside to inside:
wood / insulator / concrete / wood.

I must admit that I do not quite understand the constructive principle. The interior and exterior siding serve as forms? In this case the insulation must resist compression and there apart from the PU I do not see.
But anyway as the concrete is not breathable, it does not matter the insulation behind as long as it is thick enough.

The wood siding inside has a low effusite which implies a suppression of the feeling of cold wall which is very beneficial. But as it is also a little insulating it increases the time of transfer of calories in the concrete which is more annoying, to be seen according to the thickness.
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.az.
I discovered econologic
I discovered econologic
posts: 3
Registration: 11/05/09, 13:31




by .az. » 18/05/09, 11:57

Hello,

Here I am again after a few days of deliberate absence, because I wanted to know a little more about the construction.

To begin with, it is true that the northern climate is temperate, the presence of the sea nearby means that we have a mild winter and a fairly cold summer :) (not like in welcome to the ch'ti, winter, we are also the only region where it never snows :D ). Anyway, it is sure that good insulation from the outside is essential, and this is one of the first points on which we insisted.

It is true that the insulation + passive solar + thermal inertia should be sufficient, but it seems to me that the choice of material will prevent this inertia. Indeed, the chef turned to an expanded polystyrene + concrete wall, following the euromac2 system (sorry if I advertise: s), because it is a relatively simple principle, which fits well for thermal insulation and phonic, and in addition concrete is a locally produced resource (which is interesting to build the file).
Only problem is that the expanded polystyrene (EPS) is not very ecological, but the value for money is still interesting, and then the method of manufacturing the EPS remains among the least polluting I think, with a blowing air and few air releases.

The catch will be for the hygronomic quality of the air, and ventilation may be the place to regulate this. A VMC 2F corresponds with logic, with the recovery of calories which will always be useful in winter.

Regarding CMV and geothermal energy, I think the 2 will be done, finally the chef really wants to. Perhaps in order for this pilot operation to be properly monitored, and to determine the potential of these installations.
I know that the company has the equipment to carry out the drilling, or it has a good subcontracting at a good price, so it will be done for sure, and the goal is to make domestic hot water + underfloor heating, it all depends on the season.

Here, with all that, thank you aerialcastor, because you taught me a lot in an answer, much more than a week to navigate on websites that are often unclear and / or contradictory. Many thanks !!

Edit: I forgot to deal with the exterior, it seems to me that there will still be a wooden siding for the visual, however I do not know what will be inside. maybe wood, or a finishing coat. I read on the forum that a user wanted to remove the inner layer of EPS, leave the cement visible in order to have better inertia, the idea is interesting, but isn't there a better finish? apply a layer of brick or something similar, without degrading the wall, or adding too high costs. I am continuing my research in this area. Thanks again.
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