I’m thinking of building a light shaft through the third floor down to second floor bath, while at the same time serve a small half bath on the third via the same light shaft. I was thinking of having them open to get maximum lights, i.e. no frosted glass or anything in the ceilings. As you can see on the picture, there is a furnace on the third floor that I’m planning to supply with air via a louver in the light shaft. And finally, I was planning a Panasonic through-the-wall ventilation fan at the top of the shaft by the skylight window.
My percieved advantages are: only one hole needed in roof to get natural light in both rooms, ventilation handles both rooms
Disadvantages may be: potentially embarrasing sounds travelling in the lights shafts if both rooms are occupied (even worse smells), moisture getting trapped somehow? moisture getting sucked into the furnace and causing problems?
Please take a look at the picture and give me a verdict if this is would be a stupid thing to do (for any reason at all).
Nicoman
Replies
Man: after a big bowl of my homemade chili
UH nevermind
So you are going to have two fans trying to suck air out of the same shaft ?
The furnace being one of the two...
America is a country which produces citizens who will cross the ocean to fight for democracy but won't cross the street to vote.
Good point, I guess the furnace wins that battle. So are you saying it's a bad idea to have louvers into the shaft or that the ventilation fan won't be needed? The furnace is in a confined space.In all cases I was thinking about a skylight with vents.The chili may be an issue, I don't want it circulated in the whole house by the furnace.Nicoman
The chili would be circulated through the house by the furnace. No two ways around that.The furnace would also win the battle against the ventilation fan. That's not good for the ventilation fan.Look at the top of your shaft. See the angle of the vent shaft coming from the upper bathroom ? Continue the bottom line of that shaft on into the other shaft for a few inches. Kind of a louvre...That should keep either bathroom from smelling up the other. Since the air is not likely to drop in the shaft from the top room to the bottom, and the "louvre" I described earlier will direct the air flow from the bottom room, toward the ventilation fan.As for the furnace, I would suggest that you find a different way to supply it with air, and keep it out of this shaft.
America is a country which produces citizens who will cross the ocean to fight for democracy but won't cross the street to vote.
Thanks for the input, a lot to consider. The furnace has its own exhaust into the chimney but I was hoping to pull fresh air from the shaft, as it is connected to a vent.One thing that concerns me is that right now the furnace is off and there are no bathroom fans at all. If I hold a paper against the existing vent on the skylight it seems to blow in air into the house, very noticable when there is a puff of wind. I guess this means that the airflow in the house is pretty much static as there are no fans in operation, and if anything wind is pushed through this vent and then going out through cracks and such elsewhere. If I open the main entrance door though, the air flow goes strongly upwards.So, would a fan up there have to fight against a natural in-flow? Also, if the furnace is active I assume it will increase the negative pressure in the house, making it even harder for the fan.A confused Nicoman
Yea, I'd go with the Solatube solution. You can get them with internal fans. A separate one for each bathroom. The run to the lower bathroom can get kinda pricy, but that lightwell isn't going to be cheap either.
We have 10" in our bathrooms - turned the darkest rooms in the house into a place where we have flowering houseplants. We put 14" units in the kitchen cause it's a much bigger space to light. Their web site has sizing tables. A bonus is that you don't get the heat gain in the summer that you get with a skylight.
I'm not really keen on a SolaTube although I have looked at them. First, I believe the light coming in from a big opening above the bath tub will give a different atmosphere than a Solatube, but from a practical point I would also have to make two new holes to the roof. I already have the skylight.I guess what confuses me is the different pressure forces and how that works:Sucking in (positive pressure):
Furnace - inside air is just circulated but it needs fresh air for combustion.Pushing out (negative pressure):
Bath room fans
Kitchen fanBalancing:
Existing skylight vent - which I assume helps circulate air on the third floor
Seems and cracks around windows and doorsSo the question is, does a normal 50 year old house have over or under pressure? Is it perhaps alternating?If my house has a natural under pressure it doesn't seem to make much sense to put a small fan next to a big attic vent? I think I need a lecture here... :-)nicoman
This is one of those things that always seems crazy enough to work, then something pops up to prove why it's so crazy.
The light well idea is common enough. Have seen it done many times with older multi-unit apartment buildings as a way to get light into spaces with no exterior walls. Unfortunately, have yet to see any that were kept in good shape or didn't develop problems.
My concern is one involving local codes. They get picky about flues, exhausts and intakes. I thought a supply air source needed to be a certain distance from the exhaust air (for similar reasons offered with the chili analogy). Some of these issues developed from the Foreign Legion epidemic way back when (bad air being brought in as fresh air). You might want to run your concept by your local building department first to get their reaction.
Don't know whether it'll suit your needs, but there's a product called Solatube for getting sunlight into spaces far from roof access. The website is http://www.solatube.com. Have never used or specified it, but maybe someone else here has.
Might could be a slick idea. Probably ought to have a good-sized fan unit attached to the light well, switched to both bathrooms (if only to clear the space of heat collected by chimney-effect).
You'll want a high-gloss paint in a light color, and over a pearlescent primer to get light down to the 2nd floor bath (and some to get to the 3rd due to the angle).
Only "wrinkle" I'd add to your plan would be to rig some access panels from the the attics (yes, both) to get into the light shaft later. You might not need it, but some future owner might. Might jsut be needed for painting, too.