Solving mysterious shower leak

Q. Our bathrooms were completely remodeled in 2000. After about three years, the tub would leak into the kitchen directly below whenever someone took a shower. Not really bad, but an obvious leak after about four or five minutes.

I had the tiles re-grouted when it first started, and for several months it seemed to be fixed, but the leak started again. This is the bathroom our children used, but they are out of the house now, and it doesn't get much use.

If the bathtub is filled, grandkids are bathed, when the water runs out, there is no leak. I thought it might be the shower diversion valve, but I ran the shower for 20 minutes and no leak.

The only time it leaks is if someone is actually standing in the tub taking a shower, like the weight is causing some pipes or something to separate and leak. Do you have any suggestions as to the problem?

A. I encountered a similar problem many years ago when I was still in contracting. My partner and I were mystified about a mysterious leak, which occurred only when the man of the house took a shower. Never under any other circumstances.

Finally, out of all other ideas, we stood on a stepladder and looked at the joint where the tiles and plaster met and saw there was a very small space where water could enter. We sprayed the wall above the tiles again just above where that small space was, and finally found the source of the leak. Water could splash off the body of the person showering, especially if it is a tall person, and cause the leak.

You should stand on a stepladder and check for such an opening, regardless of how small it is, and get some bathtub caulk and seal it.

While you are at it, it may be time to apply caulking to the entire joint between the tiles and the wall above. It should take care of it.

Q. I installed insulation in the crawl space with the vapor barrier facing up toward the warm living area. Just the opposite of what you do in the attic facing it down toward the living area. Am I correct?

Also, I have crawl space vents; do you leave this open in the winter? I believe these vents do not let in a lot of air. I do have plastic sheets on top of the crawl space floor. The floor is mainly rocks over the ground. I am looking forward to your comments.

A. You are correct. A vapor retarder should always be placed on the warm side of the insulation except in hot climates where air conditioning is the main usage.

If the crawl space floor is throughly covered with plastic, it is best to close all foundation vents permanently.

Open vents admit warm, moist air during the summer, which is absorbed by all framing members. When the temperature drops and it gets colder, drier air enters the crawl space, the moisture is released, and since the vents are not sufficient to remove it, condensation is likely to occur and cause mildew. Eventually more serious problems can develop.

Many crawl spaces in the humid Southeast have suffered substantial rot from the practice of installing crawl space vents, as required by misguided building codes, and leaving them open year around. Research has proved over the years that crawl space vents are unnecessary if the soil moisture is controlled by plastic sheets covering the ground thoroughly.

It is always a good idea to enter the crawl space every once in a while and give it the smell test. If it smells sweet and free of mildew, there is no concern.

Q. I think I have a simple question: there are two areas of my kitchen's sheet flooring material that have separated from the plywood underlayment; both are where the flooring meets an oak threshold (picture of both areas attached). What would be the appropriate adhesive that comes in a small quantity that I can use to glue these two areas back down? I obviously don't want to buy a big bucket of mastic! I have some great, heavy, lead weights I can use to press the flooring down flat until the adhesive dries.

A. You can buy a small can of contact adhesive in any hardware or box store.

Q. I received three quotes for a new roof with tear-off, and two of the three said to wait until spring to do the work. One stated he would install the new roof next week while the weather could be in the low 50s. He said he could do it in one day.

Even I know you want warm/hot weather for the adhesive to seal. What is your opinion? It concerns me a lot.

A. My preference would be to wait until warm weather for the very reason you mention.

It may be all right to do the reroofing this fall, but you are taking a chance. A strong wind on a bare roof could cause serious blow-offs until the tabs seal during the hot weather next summer, if they will seal then after many months.

Q. We just had a second floor completely torn down and replaced on our vacation home, which we planned on someday being our retirement home. We considered knocking down the house and getting a prefab/modular home built, but decided to look into renovating because we loved the first floor. We put our full trust in our architect, who was highly recommended, and our general contractor, whom our architect recommended.

Before we started the job, our general contractor assured my husband that the second floor would be squared off and the walls would be plumb.

Although we drove down to visit during the construction, we did not measure or check on anything because we just do not have the know-how or building knowledge. The job is completed and to our disappointment two of the walls on the opposite sides of the house are noticeably crooked to the naked eye by at least three-quarters of an inch, and the floors slope to the center of the addition. The house looks good from the outside but the second floor is not level. This was never mentioned before, during or after the completion of the new construction. We have been told by other contractors that this could have been corrected, the floors could have been leveled, and that is what a good contractor would have done. We have also been told the only way it could be corrected now would be to tear it down and start again.

We feel that the general contractor is at fault for shoddy workmanship and for not checking on the job enough while the subcontractors were constructing the second floor. We are holding a $20,000 balance and the contractor put a lien on our house. Any advice would be so appreciated. What should we do from here?

A. There is no excuse for this sloppy workmanship. And if you hired the architect to supervise the job, he or she shares some of the responsibility for the poor outcome.

Fortunately, you are holding back a substantial amount of money. Do not pay any more.

I can't tell you if the work needs to be torn down or can be corrected. Consult an attorney familiar with residential construction and ask any of the other contractors who have told you the floor and walls of the original construction could have been straightened whether they are willing to be expert witnesses.

If none of them are willing to help you (contractors are often not willing to testify against other contractors or are often poorly suited to be witnesses), ask your attorney if he or she is working with certified home inspectors or engineers who would testify in your favor.

It is possible that, faced with a lawsuit and expert opinions, the contractor may be advised by his lawyer that he has no case and should forget getting any further payment, and drop the lien. Good luck with it.

• Henri de Marne, a former remodeling contractor turned columnist and consultant, is the author of "About the House with Henri de Marne" (Upper Access Publishing). He continues to take questions from readers for this column and his website, www.henridemarne.com. Email questions to aboutthehouse@gmavt.net.