Conventional eavestrough design involves taking rainwater and snow melt from roofs, to where it can safely drain away. Keeping them clear is a wise precaution, because heavy weather can cause the channels to block and / or overflow.
However, some architects and clients believe this obstructs the clear line of building design. When that’s the case they install built-in box gutter systems instead. These are great to behold from below. Until the heavy weather comes, and a blockage occurs somewhere up there.
Problems Relating to Built-In Box Gutters
Built-in box gutter systems are problematic owing to the nature of their design:
- They don’t attach to the outside of the fascia where they are simple to access from below.
- That’s because the system uses the fascia boards as the outside edge of the gutters.
- Therefore, problems can develop with built-in gutter systems without anybody noticing.
In theory, a waterproof membrane completes the design by going over the fascia, and under the roofing material a distance up the slope. However, the inherent weakness is these membranes can fail over time from intense sunlight, and few homeowners ever inspect them.
The uppermost portion is exposed to solar rays, and expands and contracts with temperature changes. Moreover, built-in box gutters can block with windblown debris, and eventually overflow. Almost inevitably some moisture eventually reaches the raw roof timbers, and rot can follow an infestation of damp and mould.
What’s Best to Do If You Have this System
Built-in box gutter systems are problematic based on our own experience, and very costly to repair or replace. Your best defense is regular inspection, and maintenance to extend their useful life as best one can.
Valiant Exteriors recommends an annual check and clean before the heavy rains come, followed by a careful inspection for any signs of leaky membranes, mould, and any wood rot starting. We can’t easily look under the roof membrane, however we will check for the following:
- Signs of regular water drips.
- Darker areas of wood.
- Staining and any discoloration.
- Other signs of water ingress.
Where to From Here with Your Box Gutters?
We strongly recommend an inspection if you have not maintained your built-in box gutter system for a while. You are most welcome to call Valiant Exteriors at (403)829-1661, send an email to this address, or leave a message on our website whichever is most convenient for you.
More Information
Why Are There Different Roof Gutters
Why Should I Keep My Gutters Clean
Restoring a Box Gutter in a Heritage Building (A J Van der Wall BY CC 4.0)