Question: We had new doors and windows installed in our home about three years ago. Our home was built in 1985. Our problem is with the front door and storm door. Every winter the storm door frosts up solid. We have had the installers back several times over the past three years. They have replaced the door, re-caulked everything, and checked insulation, but to no avail. Our back door is fine, absolutely no problems there. There seems to be a lot of humidity between the doors. We have opened up the screen to see if the humidity would dissipate, but that has not made much difference. It seems as though there is warm air getting between the doors and we can't figure out where it's coming from.
Several years ago we had a problem with flying ants hatching in the basement. We think they came in from the front of the house under our front door. The first year this happened we had a lot of ants, the second year not as much. We haven't had a problem since we put down pesticide. I am wondering if these ants could have possibly damaged the foundation where the wood meets the concrete. Who would I contact to look into this problem as it has become very frustrating every winter?
Thanking you in advance and I anxiously await your reply, Ursula.
Answer: Sometimes there are issues with our homes that may be a nuisance, or worse, where the solution may be more difficult to ascertain than the effort is worth. Often small issues, like your frosted storm door, may be something that can be minimized with a little effort but may be too tricky to completely eliminate.
Because we live in a climate where the temperature is often well below the freezing point for several months at a time, issues with certain areas of the building enclosure becoming frosted or ice covered may be inevitable. Even with good quality weatherstripping, thermally insulated doors, windows with sealed units and air vapour barriers, warm air may leak out and come in contact with the frigid exterior air. When this happens, condensation is likely and will often result in quick freezing, especially in certain areas. The reason your front storm door may be giving you this problem, and not the back one, may simply be location. If the front door faces the north or west side, it is more prone to the prevailing winds, which can substantially cool the doors more quickly. Also, the North wall of a home will receive little direct sunlight, which may act to melt frost that does occur on a storm door, or prevent condensation by warming the door, itself. If the front door area has a large overhang or porch, that may further prevent the warming sun from hitting the problematic spot. I would suspect your rear door does not freeze as easily because it may be in a location that is in direct sunlight for much of the daytime and any resulting frost will easily melt.
Another factor to look at is the amount of times the door is used during the day relative to other entrances. If you have an attached garage, as with many homes your age, that may be the major point of entry to the home. Especially during the winter months, many people enter and leave their homes mainly from their vehicle, through their garage. Direct exposure to the elements will be lessened, but may result in the front door being infrequently opened. That lack of use can allow any warm air that leaks around the door to become trapped between it and the storm door. This lack of air movement in the small space will help promote condensation and freezing. If the front door is the main entry point, and is used frequently, then the reverse may be true. Frequent opening of this door may allow a large amount of humid air to escape the home, which can be easily trapped by the subsequent closing of the storm door. This will surely freeze in cold weather, only to melt partially the next time the inside door is opened, and cause even more ice buildup at the bottom of the door or sill.
I am glad to see that leaving the storm door screen slightly open has made a slight difference in the frost buildup. Doing that may help remove some of the warm air that is escaping into the small cavity between the doors. Unfortunately, it may also allow quicker condensation and freezing on cold days, so the benefits may be small. Trying to reduce the relative humidity in your home may also help prevent this phenomenon, but not much else may be possible due to the configuration of the front door. I doubt the ant problem has much to do with the freezing door, but you may have a problem with moisture damaged wood in the floor structure or basement which should be further investigated and repaired.
Not all minor issues with our homes have straightforward solutions. Even though we know that warm air leaking out from around your front door is the likely cause of the frost, completely eliminating it may be too difficult for such a minor inconvenience. Keeping the relative humidity down inside your home and leaving the screen slightly open on the storm door may be the only practical options, other than simply tolerating the frosty issue.
As another year comes to a close, I would like to wish everyone a Happy New Year and thank all readers for their kind comments, suggestions and most importantly, all the excellent questions. Please keep the inquiries coming so that I may continue to provide insight and solutions to your home issues in the coming year.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the past president of the Canadian Association of Home & Property Inspectors -- Manitoba (cahpi.mb.ca). Questions can be emailed to the address below. Ari can be reached at 204-291-5358 or check out his website at trainedeye.ca.
