All about bay window inspections and maintenance

A bay window is a space that extends beyond the facade of a building and is openly connected to the intended room. The exterior is bordered by window frames, the covering of which, along the parapet of the sill, is called a windowsill. The floor of a bay window is usually level with that of the room to which it belongs.

The bay window's roofing may be in good technical condition and will last for years. However, a precise expected lifespan is difficult to predict and depends on various factors, such as weather conditions.

The bitumen roofing on the bay window may be in poor technical condition, in which case it can last a maximum of 2 to 5 years. A precise expected lifespan is difficult to predict and also depends on various factors, such as weather conditions. Replacing the bitumen is inevitable over time.

The bitumen roof covering on the bay window may be in poor technical condition . In that case, it should be replaced immediately. There is a very real risk of leakage, which could cause further (consequential) damage.

The bay window roof is not covered with a covering, but is made of concrete . It's possible that the drainage and waterproofing systems are inadequate or not waterproof enough. The reinforcement in the concrete can then be affected by moisture, rust, and damage the concrete. In that case, we recommend applying a zinc or bitumen covering to the roof, after which it will function properly again.

• The new compacted concrete (in relatively newer homes) poses less of a risk.
• Pay particular attention to the older, coarse structure of the concrete structure. If coarse gravel is visible, the risk of moisture ingress into this stone-like structure is automatically greater.
• Any moisture already present in the concrete will dry naturally if the top is 100% sealed.
• If in doubt, consult an expert. The cost of repairing any concrete damage caused by rusting reinforcement can be substantial. Therefore, it's important to be sure whether there is concrete damage or a risk of concrete damage.

The bay window roof can also be covered with a newer version of concrete slab (compacted) and function perfectly. Drainage and waterproofing are usually sufficient. If at any time the concrete is no longer sufficiently waterproof, a bitumen or zinc roofing can easily be applied to this section.

• There's a connection between the bay window roof and the house's facade. This connection is usually made waterproof with a lead flashing (foot lead). This lead flashing runs through the cavity wall of the facade and is attached to the inner leaf. Rainwater absorbed by the facade and seeping down is thus forced out. If this lead flashing isn't present, it will need to be installed, or you should be aware of the moisture risks that may arise or may already exist.
  • If the bay window's roof is located under a substantial overhang, a compression strip can also work well. Depending on the situation and the facade load from rain, one or the other solution can be chosen.
  • For masonry, the best solution is to remove strips of brick so that the lead can be installed in the cavity against the inner leaf. Another solution would be to grind the lead at least 4 cm deep into a joint. If installing under a window frame, a professional is recommended.

• The foot lead as described above must be (partially) replaced if it is in poor condition and recovery or repair is no longer possible.
  • Simply clamping the lead seal and closing the joint is not a proper repair, but it is probably the most commonly used method.
  • For masonry, the best solution is to remove strips of brick so that the lead can be installed in the cavity against the inner leaf. Another solution would be to grind the lead at least 4 cm deep into a joint. If installing under a window frame, a professional is recommended.
• The lead seal described above can, of course, also be (partially) repaired. This can be done by patching cracks in the seal with self-adhesive bitumen tape, available at any hardware store. As long as repairs are possible, we recommend postponing replacement.