A bridge cavity is a hole that occurs at the door threshold. The gap can be filled in by lowering the inner leaf of the door threshold. In some cases, a door can be removed to make the space larger. In such a case, a DPC may be necessary. Then, the gap can be filled with a dummy window or with a DPC that is made to fit a door.
A new door is installed in a softwood box frame and fixed or glued to the existing softwood door frame. The new door sits further inside the EWI, reducing thermal bridging around the existing opening. The door is reinforced with a steel angle and insulated with a polystyrene that is suitable for below ground insulation. This method will prevent the cold drafts from forming and will prevent the door from opening in the winter.
Cavity closers can also be used at the threshold. These devices are made of uPVC and cannot support the floor. Therefore, a wooden floor board cannot be used to bridge a hollow cavity. Instead, a softwood box frame with a steel angle is used. It sits further inside the EWI, minimizing thermal bridging around the opening. An additional layer of XPS and celotex is added to the inner leaf and the lowered wall.
A new door is installed into a softwood box frame and glued or fixed to the frame. The new door sits deeper inside the EWI and brings the existing opening into the thermal envelope. The new doors reduce thermal bridging around the existing opening and reduce the need to insulate the entire opening. The steel angle and polystyrene above the threshold are used to reinforce the threshold and provide insulation.
A cavity closer is used to eliminate thermal bridging at the door threshold. It prevents thermal loss in uninsulated cavity walls by lowering the threshold. It is an important consideration in Building Regulations Part L (Foam and Concrete) and Part L power-saving. By bridging a gap between two walls, the door will remain warm and conserve energy. When a new door is installed in the same way, it will sit closer to the outer door, preventing thermal bridging.
The best way to bridge a gap at the door threshold is to use a cavity closer. This product acts as a seal against external moisture and damp and prevents heat loss through the gap. It is important for Part L building regulations and for fuel and power conservation. A cavity closer will keep the building warm while preventing the thermal bridging at the threshold. It will also reduce the risk of fire. However, it should not be used on a regular basis.
In addition to a cavity closer, a door threshold can be built into the softwood box. Then, the new door is glued or fixed to the new frame. The new door sits further into the EWI, bringing it into the thermal envelope and eliminating the need to insulate the existing opening. Its reinforced steel angle will also be insulated to keep out cold. This way, the gap at the threshold will be a barrier between the door and the floor.
Using a door threshold to bridge the gap between the door and the wall is a great way to reduce thermal bridging. The gaps in between the softwood box are easily insulated, but they are not ideal for a door threshold. The best way to bridge a cavity at the entrance to a home is to use a solid wall. Adding a solid wall between two walls will make the house warmer and the door and wall more durable.
A cavity closer can be an effective thermal bridge between two pieces of masonry. By extending a DPM and DPC to a door threshold, the gap is closed. By installing a cavity closer, you will reduce thermal bridging around the door and the rest of the wall. The door will be closer to the wall, which reduces the amount of energy that is needed to keep the building warm. The process will also help in extending the thickness of the floor.