Ground under wood deck gets too saturated
Q. Many years ago, a porch/deck was constructed across the back of my ranch-style residence. A little more than half of this structure has solid flooring and is now covered with an Otter Creek sunroom. The deck portion extends beyond the sunroom and is constructed with six-inch, pressure-treated lumber. It gets complicated because the ground beneath was never excavated, except for a generally four-foot-wide passage that leads into the basement via a standard doorway, and the entire structure is enclosed with pressure-treated plywood and siding built on top of railroad ties. Inside and under both the porch and deck, the fairly heavy sand ground slopes away from the basement walls with about a 20-inch clearance at the top and four-foot clearance at the bottom. The angle of the slope seems about 15 degrees, to my amateur eye. When there is precipitation, water runs down between the deck boards onto the ground below. The sand does not seem to wash away much, although it does get quite wet. Water drains more into the piling foundation, however, and that stays damp for a longer period of time perhaps too long because those ties are deteriorating. It would be great if no water got below at all.
I'm wondering if it would be reasonable to apply caulk between all deck boards to achieve this. I realize the slope of the deck would have to have the correct slope for drainage. Please provide your thoughts and/or suggest better solutions.
A. I doubt that caulking would be effective for long, if at all, unless the boards are close together almost touching. To be successful, caulking needs to be applied to clean and opposite surfaces. This is not a situation found with deck boards that have eased (slightly rounded) edges and are hard to clean between boards. One solution may be to apply a water-and-ice protective membrane or rubber roofing to a clean deck and cover it with pressure-treated plywood. The edges of each sheet of plywood should be caulked before the next sheet is pushed against it. The plywood will also need to be painted, and kept painted in a timely fashion, to keep it from developing splinters and its top layer from cracking. Looking at your photos, an easy fix involving a slightly sloping metal or plastic roof suspended below the joists would be hard to accomplish without major surgery because of the solid plywood skirt around the deck. Over the years, several manufacturers have developed various coverings for flat-roof decks used as outdoor living spaces above finished spaces, but they haven't lasted long. If anyone has solved this problem satisfactorily over the test of time, please let me know.
Q: I am not an electrician, but I think an unbalanced leg in the panel could be the culprit for a high electricity bill. Am I right?
A: Sorry, but no. An unbalanced leg does not affect the price of power.
Q. What is your opinion of the E-Z Breathe home-ventilation system and similar products? Do they perform as advertised?
A. I have no experience with the E-Z Breathe 400 Wave Whole House dehumidifier. The product retails for $1,700 (substantial discounts are available) so give it serious thought before buying. Because the company claims there's no need to empty a reservoir unlike other dehumidifiers and that it provides six to 10 air changes per hour, it must be connected to the outdoors. If you subscribe to Consumers Reports, check to see if they have compared it to other dehumidifiers.
Q. Three years ago, we purchased a small cottage on Mills Point, in Colchester, Vt. The previous owner had rebuilt it from the ground up with new Thermopane windows and insulation with a poly barrier. I think he created a condensation problem. Three years ago, I painted the whole cottage with latex. The clapboards on a northeast wall are becoming badly checked with what looks like dry rot. When I painted three years ago, a few blemishes could be found on the wall but nothing compared to how it looks now. I believe that the vintage of the spruce clapboards is the same as the rest of the cottage, where the walls look fine.
The roof is asphalt shingles, and fairly flat. There may be an ice stop or a membrane under the shingles, I don't know. There are no signs of leakage inside. Also, the paint in the affected area is not bubbling, which I assume would happen if moisture were trying to get out. The cottage is unheated and only used from May to October; it is on piers with a totally open crawl space.
I have had three roofers and two builders look at the situation, all with different answers. One said it was from winter ice dams, where the pitched roof meets the almost flat roof. Another said that the edge of the roof was not finished properly and the water was leaking down between the poly and the outside wall. One thought it was from snow buildup. Another thought that the overhang was not enough and I should add a gutter. The last one said I would like to sell you a new roof, but that the roof is not the problem; it's a moisture problem. There is a bathroom adjacent to the room with the problem, but the outside wall of the bathroom is fine, and there is an exhaust fan in the bathroom. The kitchen is in another part of the house, and the outside wall where the stove is seems fine. So now that I have bored you to death, I need advice on what approach I should take to this problem.
A. For condensation to occur, there needs to be a dew point. This would require a differential in temperature between the outside and the inside and a relative humidity on one side that would reach the saturation point when in contact with the colder surface be it inside or out. In cold climates, where buildings are heated for many months, a vapor retarder is installed on the inside to slow the transfer of indoor moisture through the wall components toward the colder outside surfaces, where condensation would occur. In hot climates, where air conditioning is needed for most months, a vapor retarder is installed on the outside because the hot, humid air can condense on the inside walls. So, considering the climate and the fact that the cottage is not used in the winter, we can dismiss the condensation issue as the cause of the failing clapboards. Besides, if that were the problem, it should manifest itself in other areas, and paint would most likely fail as well. An unheated building is also unlikely to have ice-dam issues.
Are all the clapboards in the entire section of the affected northeast wall showing decay from top to bottom or only on the lower part of the wall? Could these clapboards be subject to the splashing of water from the roof onto the ground, a patio or a stoop? Is this wall deeply shaded by trees, particularly evergreens? The fact that they are badly checked indicates that moisture has penetrated them because of inadequate protection. Once wet, they will dry from the outside much faster than their back surfaces, and they will curl, check and crack. Not having seen the condition or the environment, it is difficult for me to be more helpful.
Q. We had placed a good grade of Wilsonart Laminate flooring in our kitchen about nine years ago. We picked up a current swatch of the same (2-by-2 feet) from the company that did the previous installation, laid it down on the old at different points throughout the kitchen, looked at different angles and in different lighting, and saw practically no difference at all. We would like to place this same flooring against the older kitchen flooring to continue in and throughout the living room. What are your thoughts on what this would mean to the resale value of the home?
A: Because you have had such good success with the kitchen laminate, it makes sense to use the same flooring in the living room. Laminate flooring is durable, and any bias against it from a prospective buyer will be a personal one.
Q. I have an attached two-car garage with living space above part of it. Two of the four walls are backed up against the living space. A few years ago, my husband insulated and added plywood to the walls, and I had two insulated overhead doors installed this year. Because the garage was insulated, we have experienced mildew on the inside of the garage walls and doors from moisture coming off our vehicles during the winter months. Now I'm afraid it will be worse with the new doors. What can I do to transfer the moisture to the outside without allowing more cold air to enter?
A. Tightening the garage has increased the relative humidity inside, whereas there was enough air exchange before the improvements to dissipate the extra moisture. Any means of ventilation you provide will bring in cold air. A room-size, air-to-air heat exchanger might help, but because the garage is not heated (and it is best not to heat a garage in cold climates where road salt is used to keep roads ice-free), it is still going to bring in cold air.
Q. I bought a ranch-style house built in 1964. I want to finish a basement and was wondering where to put the vapor barrier. I removed the paneling that the previous owners had in place and found their vapor barrier was installed directly to the block. They did not insulate. Some moisture has accumulated on the vapor barrier nothing significant. I will be insulating these walls with faced fiberglass. Thank you for your help.
A. The previous owners installed the plastic vapor retarder against the block walls to protect the paneling from moisture that may come through the blocks. This was the thinking some years ago. If the moisture that you see on the plastic is on the block side, it is caused by moisture coming through the blocks. But if it is on the basement side, it is likely caused by the condensation of interior moisture getting through the joints in the paneling and reaching the colder surface. The current thinking (probably subject to change again) is not to put a vapor retarder to allow the passage of any moisture in both directions. It is advisable, however, to apply at least one-inch-thick rigid insulation against the block walls to prevent condensation. But a word of caution: The previous owners did not insulate the walls. Unless you are sure that: 1) there is an effective foundation drain; 2) the backfill is made of coarse material; and 3) the grade slopes away from the foundation, you are taking a risk that frost can penetrate deeply into the ground and crack the block foundation walls. It is safest to insulate only down to two feet below grade to allow some heat to warm the soil and keep the frost at bay.
Ÿ Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Write to him in care of the Daily Herald, P.O. Box 280, Arlington Heights, IL 60006, or via e-mail at henridemarne@gmavt.net.
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