Expert: Dan Griffin - 1/23/2009

Question
What happens if water runs and stands under house (5 blocks high) 2 to 6 inches for 6 weeks before repair? Background info-new home, moved in June, 2008.  During move person connecting the washer and dryer asked if we knew water was standing under house.  This is first knowledge by us.  Found out later other subs had pulled black roofing materials to lay on while working under.  A lot of actions were taken before french drains were put in place.  We thought this was over, but crowning molding and baseboards starting separating, came back and chalked.  Now it is happening again.  House is 2500 sq ft.  Our retirement downsized home.  We are very upset.  Don't feel we can believe our contractor.  Says it is the house settling.  What are your thoughts? M

Answer
Marilyn, I am so sorry ou are having these frustrations.  I don't quite agree with the term settling.  Remember this a huge collection of diverse materials from multiple sources that have been exposed to various climates and conditons.  Most of the issues have to do with moisture content.  Boards shrink as they dry, drywall nails pop, disturbed soils recompact over time.  Some things are cause for alarm and others are the nature of the beast.

The foundation has a footing that meets your areas frost depth.  It sounds like you have foundation walls that are block.  Footings and their bearing capacities are based on the soil type under the footings.  High plastic index (expasive) clays are very prone to changes between wet and dry and can effect foundations.  Sand, gravel, stone, and shales are relatively unaffected.  If your founddation was adversely affected you would probably see cracks in the block walls and/or footings.  It sounds like your site has a ground water problem that was finally solved by installing a French drain system.  It could be argued that a good French drain system should have been installed from the beginning.  Wet subsoils and poor drainage can contribute to very high humidity levels in a building and all wood reacts to humidity levels.  I'm sure you have had a door that swells a bit when the seasons change and sticks.  Winter heating months tend to be very dry compared to other times of the year and wood work will shrink to its smallest dimension.  This shows up on large expases of wood flooring (think about a gym floor) and long lengths of trim work especially.  All wood has some moisture content when purchased.  It may have been outdoors at the lumber yard, truck, job site, etc.  If the moisture content was high when installed, it will shrink as it dries, causing the symptoms you describe.  Uncontrolled moisture levels can cause mold, so these issues must be solved.

Things that can be done.  Control humidity levels with mechanical systems.  Humidifiers on furnaces for winter months, especially if you have static problems or "dry nose" problems.  Dehumdifiers for wet seasons, proper exterior grading to keep water away from the building, gutters and downspouts to get water well away from the structure.  Avoid planting and flower beds close to the structure.  Make sure kitchen and bathroom moisture is ducted to the outdoors, not dumped in the attic.  If the French drain has solved the moisture problem, you are waiting for the structure to reach a point of equilibrium.  Make sure the French drain system is taking the water away from the sturcture by pumping or draining well away from the stucture.  Run a dehumidifier in the crawl space temporarily to get things dried out from the standing water problem.  This may well take a week or more, but waiting for mother nature to deal with it could well take months.  Talk with your builder, express your concerns.  With these few facts, and ask for his advice and input.  Get a commitment to replace woodwork that cannot be dealt with by caulk.  Painted trim can be caulked and repainted as long as the gaps are not substantial.  Once the building is stable, I would like the gaps to be 1/8" or less as a dimension to discuss.  Try making your builder be the expert, don't expect absolute perfection unless you paid for it, remember the old line about flies and honey.  Don't abrogate your rights, but save the law suit talk and threats only if the honey method doesn't work.