Rocky Hill of Canyon Lake, Texas, asks:
"What’s the best way to repair my leaking foredeck hatch? I don’t want to replace the entire unit, because it isn’t cracked. It just leaks."
Don Casey replies:
There are three types of hatch leaks: around the frame, past the gasket and around the lens. To fix a leak around the mounting frame or past the fasteners, remove the hatch or hinge, clean away all the old sealant and rebed the hatch with fresh sealant. Be sure to squeeze the sealant so it comes out all around the frame. But don’t overtighten the fasteners, because this could squeeze the joint “dry,” which will invite more leaking.
If the leak is coming past the gasket—over time they do tend to get compressed—the only permanent fix is to replace it. The hatch manufacturer should be able to provide the correct replacement gasket, but you might also check with a local rubber/gasket supplier to see whether they carry the proper extrusion.
Finally, if the leak is between the lens and the frame the sealant has failed and needs to be replaced. To do this you must first remove the lens by slicing the sealant holding it in place. Slice the sealant along both the outside perimeter of the lens and the inside lip of the frame. Once you have removed the lens from its frame, clean all the old sealant from the lens and from the frame.
Reinstalling the lens is a two-step process. First center the lens with spacers and a bead of sealant on the bottom lip of the frame. Use the same adhesive silicone that is used to secure windows in office buildings—either GE SilPruf 2000 or Dow Corning 795. Keep the spacers in position until the sealant has solidified enough to hold the lens in place. Then remove the spacers and fill all the remaining gaps between the lens and the frame, using the dispenser tip to push sealant into the gaps. Dress the sealant with a plastic spreader and let it cure. The lens should now be leak-free.
If the lens is scratched or crazed, this is a great time to install a new one. After you have removed the scratched lens make a pattern from it and then cut a new lens from either acrylic or polycarbonate. If this is a challenge, get a professional to cut the new lens. Lens replacements are available from Select Plastics (selectplastics.com).