Attached Greenhouse / Conservatory
We are planning a project on the coast in CZ6.
The proposed new house is attached to an existing house by means of a conservatory or greenhouse.
We are assuming the floor will be some kind of crushed stone base to promote drainage when watering. Thus no slab and likely no vapor barrier. This space will be unconditioned. If this is actually used as a green house this space is going to create an awful lot of moisture. With all the glazing it’s also going to see big temperature swings.
Has anyone detailed these before? My main concern are the exterior walls of the conditioned homes that attach to the green house. The green house itself is mainly masonry, metal and glass. The attached houses are wood framed and clad.
Appreciate any input
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Replies
Hi Cal! Attached greenhouses definitely make me nervous; high levels of heat and moisture equate to high vapor pressure, pushing moisture toward cooler, drier spaces--i.e., inside the home. I would want robust insulation and vapor control on the exterior of the framed walls-ideally a thick layer of foil-faced polyiso. I would also want automated venting for the greenhouse, so it doesn't get excessively hot.
Consider separating the green house by a few inches that will limit the risk from the excess moisture from all the plants.
If you want a real green house, you would want 20 feet of separation so as not to block the light from the side attached to the house.
Walta
Maybe have the roof continuous from the house to the greenhouse, but separate the walls of the structures as suggested above. No need to build a known problem into your new house.
plumb_bob,
I like that idea. Maybe a small breezeway on each side which becomes usable outdoor covered living space?
Be very careful sealing that roof off from the greenhouse. I have a project I'm supervising right now that is rebuilding a corner of a house (wall and roof framing), because humidity from an attached lean-to greenhouse got into the soffit over decades and caused problems. I was called out to look at some cracking in the walls, which looked like settling, but was really the interior drywall crushing due to lack of support from the internal framing within the wall.
Build things to be completely sealed from moisture and you should be OK. Moisture drive will ALWAYS be in the direction FROM the greenhouse TO the home in this assembly. A vapor barrier on the exterior would be a good idea to keep the greenhouse seperated from the "house" part of the structure.
Bill
Yes, if there is an opportunity to separate them I would strongly advise taking it. Otherwise potential to knockdown and use elsewhere?