QUESTION -- Our cottage is an A-Frame, with a front window wall: 75 per cent of the front is windows and the siding is pine D-logs. Since it was built, rain leaks in, but only if it is a really bad storm. We thought it was the windows, but Jeld-Wen came and inspected, and determined that there was no problem with the windows. We had our contractor take off the D-Logs, replace the Blue Skin around the windows, but that did not fix the problem, either. Any ideas?
Pat Chorney
ANSWER -- Moisture intrusion through or around windows is one of the most common complaints of newly built homes. The cause can be difficult to pinpoint because the source of the problem is often hidden. We will discuss a few possibilities, but opening up the walls further may be the only solution to finding the reason for the leakage.
In reality, there are only three possibilities. The first two are leakage through or around the window itself. Since your contractor has removed the siding and reapplied new waterproofing membrane around the windows, that is not the likely area of leakage, but we still may not be able to rule it out if that hasn't been sealed properly. I would check above the windows to ensure there are proper metal drip flashings installed. These must be installed underneath the building paper or housewrap, but that will not be visible. Even if that was done incorrectly, the new Blueskin membrane should prevent water from seeping in behind the flashing. If you don't see metal flashings above all the window frames or brick mould, that is the first place to look for repairs.
If flashings seem to be in place, the next possibility is that water may be leaking through the windows. Since it can't go through the glass or the frames, the seals around the glass units or the moveable sashes are the only options for leakage.
In most newer windows, the glass sealed units are held in place by stops and synthetic seals or weatherstrips. If these are loose, improperly secured, or ill-fitting, high pressure water can penetrate the window. If the hardware that pulls the windows tight to the seals is loose or damaged, seepage is also possible.
If there is a small amount of leakage, drains near the bottom of the window extrusions will often take care of this by allowing it to clear the windows before it can penetrate through to the inside.
If either of these window issues are the culprit, spraying water on and around the windows with moderate pressure from a garden hose may show results.
This was likely done by the window reps who inspected your property, but they may not have been that diligent. I would recommend trying it yourself for a prolonged period, with someone inside checking for leakage with a strong flashlight. If that test proves negative, the final possibility must be explored.
Many times water that appears to penetrate a building through the windows does not actually enter where it is visibly leaking. If moisture is entering the wall cavity near the top, it will normally run down the sheathing or framing before it hits a horizontal surface. The majority of horizontal surfaces in many exterior walls are the framing above or below windows. Water entering high up on the peaked wall at the front of your cottage may travel a fair distance before it settles on the framing above the windows, or on the window frames. With a strong wind, the high air pressure can force this moisture toward the inside of the gap between the frame and the wall studs. If there is enough water, it will eventually find its way in behind the window casing to the inside walls. Taking off the casing on the most problematic windows and trying the hose test on the entire exterior wall may confirm the problem is elsewhere.
If that test results in a positive outcome, or even if it does not, leaving some of the window casing off until the next rainstorm may provide more insight into the source of the issue.
If none of these tests shows a definitive cause-and-effect relationship, more invasive measures may be required.
Inspection of the wall assembly with a thermal-imaging camera may be somewhat helpful, but may only show gaps in the insulation, or where water has made framing or insulation wet. It is unlikely it will be able to pinpoint an exact area of contention.
When checking the wall assembly for defects, the exterior is the likely point to start. You have stated the imitation log siding was removed, but you did not elaborate on the status of the exterior wall. Is there black building paper or housewrap on the outside of the wall sheathing? Is this installed properly with lower areas overlapped by the upper sections and is it complete or missing in critical areas?
It may also be necessary to remove this thin membrane to inspect the condition of the wall sheathing behind it. Looking for any areas with large stains, mould, or other signs of water penetration may yield further answers. If not, complete replacement with new housewrap with minimal seams may prevent future problems.
Investigating and diagnosing a point of moisture intrusion in or around windows can be one of the most difficult tasks for new homes. If leakage through the windows is ruled out, removing casings or exterior siding and other components may be required to identify the true culprit.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the president of the Canadian Association of Home & Property Inspectors, Manitoba (www.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 www.trainedeye.ca.
trainedeye@iname.com
