Baseboard caulking- do we need it?
Our green home is almost finished, and we noticed that there is no caulking from the baseboards to the flooring. The builder says nobody caulks them, but I think we should do so for three reasons: 1. It looks better since gaps are concealed. 2. It stops any air leaks and 3. When liquids, dirt, dust, etc., gets between the baseboard and the flooring, caulk keeps it out, and so there is less risk of mold, etc.
The builder says the caulk won’t stay when the flooring moves (it’s hardwood and tile all over), so it’s a waste of time and besides, they’ve never seen it done. Their solution is quarter-round, which isn’t for the style house we have.
So, is it worth the effort to caulk all over?
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Replies
Will,
Like your builder I've never seen the junction caulked. If I were you I'd caulk a small area and leave it for a year or so. If you think it was useful, do the rest.
Malcolm, I should have mentioned earlier that we'd had that area caulked in a house 20 years ago, with no apparent ill effects. That's part of what puzzled me with this new one.
The builder and I previously discussed your suggestion, and I may come back to it later when they are done completely. Doing it myself later means extra work in terms of moving furniture, etc. but that's an option.
Baseboards shouldn't have vertical gaps from bottom of baseboard to flooring big enough to be noticeable. If there are large vertical gaps between the baseboards and the flooring something is weird (flooring uneven?) I've definitely scribed some baseboards/toekicks to uneven tile before, it's a pain but doable for a trim carpenter.
Quarter round is usually for when the flooring was done after the baseboards were in, covering the expansion gap. If there are horizontal gaps then the flooring wasn't installed correctly (the baseboard should cover the expansion gaps.)
I caulked the gap between subfloor and drywall bottom with spray foam (Daptex I think) whenever I had the baseboards off for painting in our house. I can't discern an effect on air infiltration, though there might be one. However, it has been useful for limiting spill penetration in a couple places.
Caulking baseboard to flooring would have the same spill benefit, but I'd question whether it would stand up to movement of a floating floor at least. If tiles are moving enough to cause caulk failure, you probably have a bigger problem.
If you detail the drywall airtight, or have some other air barrier already in the walls -- which you really should if you want an energy efficient "green" home -- then caulking the baseboards isn't necassary for air sealing and doesn't gain you anything. As others have mentioned, I've not seen baseboards caulked either.
You shouldn't have large gaps between the baseboard and the floor. The baseboard is usually pressed into place as it's installed so that it's a reasonably tight fit against the floor with no visible gaps. Your builder is correct that the floor will move (wood floors expand and contract with changes in humidity, and also a little with temperature), which could cause the caulk to seperate regardless.
You generally don't want trim to be part of your air barrier. Air barriers should be further in, in more solid locations.
The one place the caulk might help is to keep dirt out of any small gaps, but keep in mind that caulk tends to attract dirt itself, so it might actually make things worse.
Bill
Caulk always fails especially where different materials intersect and then can cause other problems (places other than floor/wall more problematic especially involving moisture)
There should be no air leakage problems if the building envelope is properly detailed and demonstrated with a blower door test and leakage would not occur nor be controlled at the wall/floor intersection.
Well installed baseboard should be tight and parallel to the floor (as mentioned above and not require a shoe mould. If shoe mould needed and quarter round not appropriate another shape like square edge stock could be used.
Caulk collects a lot of dust. Even painted.