Sealing storm windows

[Pat the RiverRat]

I just received all the new storm window I ordered for our house. I read over the installation instruction even though its a no-brainer. Now, I know it says not to caulk the bottom of the window to allow water to escape. I test fitted one and the fit was so tight there is no way water will run out the bottom. If it does it will drain slow enough to cause damage anyway. So what's the point? Storm window are supposed to help keep air out. By not sealing the bottom this defeats the purpose. Not to mention most of the weatherizing site say to seal all cracks and windows completely. So what is right?


Pat

[Under_Miner]

Well Pat, where I come from caulking is required at all points at a window, including the sill. Regional codes may vary however.



Caulking shall be provided where required to prevent the entry of water into the structure.

Caulking shall be provided between masonry, siding or stucco and the adjacent door and window frames or trim, including sills, unless such locations are completely protected from the entry of rain.

[Bumblerazz]

I think it also may depend on what you are trying to keep out with a storm window. If it's just rain and wind from a "storm" then a free space at the bottom is acceptable to prevent moisture build-up between outside and inside.

If you have secondary windows to prevent heat loss or the exchange of cooled/ heated air, then caulking is a must.

I guess if you are sealing the storm window but have high humidity inside that condenses on the inside surface of it, then you may want to have a small space for air exchange around the inner window so that moisture can re-evaporate.

[Pat the RiverRat]

Thanks guys. My storm windows are a secondary window as my house still has its orginal 1922 single pane double hungs. I'm not too concerned about moiture build-up as the sashes are loose enough to allow some air movement.
Thanks for the help!

Pat