Basement Window Leak

[rodster]

My house has a concrete block foundation. We had a 6ft window installed near the walkout door. They built the hole for the window when laying the blocks. They then put treated lumber in the hole, followed by the window, which appears to be a standard vinyl window. On the outside the siding guy made a frame out of aluminum flashing or fascia material. This arrangement is leaking. I have tried calking around it several times, but it still leaks pretty bad.

Any ideas on how to seal this up? Do I need to remove this flashing/fascia type material and replace with something different?

Thanks

[Sweep]

It all depends on the flashing detail especially at the sill. A drawing or a photo would help.

[rodster]

Here is a picture of the outside. It doesn't appear that the silicone caulk is adhering very well to the concrete or the metal.

[Pokey]

In my opionion i would have a piece of flashing bent that would tuck up under the siding that would then be bent in a z shape that would cap the top of the window trim. Visually it should look ok if you use matching aluminum coil stock to make the flashing. Hopefully that will do the trick.

[Sweep]

I agree with pokey, the head should be flashed up under the siding and the flashing should extend all the way to the window frame and cover that joint too.

As for the other joints, before removing the metal try removing all of the silicone sealant and applying a one-part polysulfide sealant. Silicone does not adhere to surfaces very well even thought it is very flexible.

Polysulfide is less flexible but it adheres better and can be painted which protects it.

Polyurethane is the other choice but it is not very flexible, adheres so well that it is virtually impossible to remove, and can be painted.

Silicone is best used in tight joints where only its face is exposed to the weather. It only works well if there is a foam rope placed behind it to allow it to form an "hour-glass" profile. Perhaps it could be used between the window frame and the metal trim (only if it is placed between two parallel metal faces) and Polysulfide could be used at the other more exposed joints. Any metal butted joints (like at the mitered corners) must have sometning behind them to prevent leaks. Ice & Water Shield or Vycor could help there.

If you get desperate there is a self-adhering (peel & stick) modified asphalt waterproofing tape with a thin aluminum face sold at Home Depot. It will seal anything permanently but looks like hell. Use WR Grace's WB primer on any masonry for a permanent bond. Perhaps the metal could be removed, the tape applied and then the metal reinstalled. If it is completely covered, Ice & Water Shield would do the job.

Any waterproofing tape must be rolled with a small heavy steel roller or it won't adhere properly.

[rodster]

Those sound like good ideas. Thanks