Topic 2 – Replacing Windows and Doors and Improving Building Envelope

Replacing Windows and Doors

Before replacing any window or door, it is necessary to first protect the structure and finishes.

After protecting the area from any unwanted damage, the interior trim can be removed. This can be done by scoring around the trim with a knife, so paint will not be damaged when trim is

removed. If the trim is to be kept for re-installation, care must be taken when removing it.

The next step is to take off any removable components, as this will make the door or window lighter to handle when removing. Once components are removed, the fasteners holding the door or window will now have to be removed or cut. There are two different ways windows and doors are attached into an opening, one uses a nailing fin or flange, which is then covered by exterior finishes. The other type is attached with nails or screws through the brickmould or frame. For each type a different removal process is needed.

For a window or door with a nailing fin, the fin and the fasteners used to secure the window/door in the opening are beneath the exterior finishes. The fin has to be cut from the window/door frame using a reciprocating saw between the exterior finish and the exposed portion of the window/door frame. Once cut free, the frame can be removed from the opening. All this must be done carefully to avoid damage to the interior/exterior finishes.

For windows/doors fastened with nails or screws through the brickmould, the moulding must be removed to remove the frame from the opening. Again, the work must be done carefully to protect the exterior finish from any damage.

Maintaining the Building Envelope

The building envelope is the assembly of components which make up a sealed physical separation between internal building space and the external environment. When a building is renovated the building envelope can be cut or damaged and will then need to be restored to re-create the best possible seal.

The building envelope includes both above grade and below grade components. The following is a list of their components. Above grade:

Below grade:

Improving the Building Envelope

There are some things that can improve the building envelope that already exists. This can help reduce air infiltration and heat loss in winter or heat gain in summer. This will reduce energy costs and improve the environment. Some ways that this can be improved without incurring large costs are as follows.

Weather stripping

With regular use over time, weather stripping on doors and windows does wear out and

become inefficient. Also, weather stripping on attic access doors and crawl spaces can wear out. Before replacing the weather stripping, first check the components and frames for proper operation and damage. Any problems need to be fixed first. Then, install the new weather stripping. The new weather stripping will again reduce the air and moisture leakage.

Vapor barrier

Older buildings may have little or no vapor barriers. For them, it is not practical to remove all the interior wall finish just to install a poly type barrier. However, if a barrier is needed there are paint products that can be applied to interior walls and that comply with the NBC standards. Also, to stop air/moisture infiltration at wall receptacles, a foam gasket can be used under the cover plate.

Insulation

Lack of insulation can cause heat loss in the ceiling, walls, around windows, doors, and any wall openings from mechanical systems. Some solutions:

Review Questions

1. What are two different ways windows and doors are attached?
2. How can the nailing flange/fin be cut when exterior finish is to remain?
3. What should be done if an R.O. has material that is unsound?
4. List the components that make up the building envelope above grade.
5. List the components that make up the building envelope below grade.
6. What 3 areas of the building envelope can be improved without incurring large costs?

Answers

1. Nailing fin or flange and brick mould.
2. Using a reciprocating saw between the exterior finish and the window frame.
3. The unsound material should be removed and replaced.
4. 1. Roof covering
   2. Exterior finish
   3. Air barrier
   4. Windows and doors
   5. Framing
   6. Insulation
   7. Vapor barrier
   8. Interior wall finishes
5. 1. Moisture barriers and damp-proofing
   2. Foundation wall
   3. Framing
   4. Insulation
   5. Vapor barrier
   6. Interior wall finish
6. Weather stripping, vapor barrier, and insulation