Windows: In Depth

When installing new or replacement windows, there are a number of factors to consider. For instance, when I bought my new windows, I wanted a model with an insulating quality – many window manufacturers include this as standard now. What this feature includes is essentially two panes of glass with a layer of gas between the two panes – this helps to ward off the extreme heat and cold we experience in Iowa. Some brands will even have a glaze-like property that filters out unwanted (UV) rays that can fade carpets or upholstery over time.

From what we could see, the older windows were replacement windows, anyway. The windows themselves were attached to the trim pieces around the edges, and the trim pieces were nailed to the house which is fairly common practice for this type of installation. Once we removed the trim from the exterior walls of the house, the windows came out fairly easily. We could then reframe as necessary.

In the dining room, the older windows weren’t very solid to begin with – this was because the ORIGINAL, original windows were so much bigger (about 80”!) and the newer framing would have been difficult to put in place given other constraints. Because we had no siding outside and no drywall inside, there were no obstacles to work around!

The kitchen window framing wasn’t in great shape – due to the flat roof over the kitchen, this area of the house had patches of rot here and there that we replaced as they were found.

The Kitchen windows, again.

The other windows we replaced were in the bedrooms. The new window in the master bedroom was taller and thinner than the window before it, so we ended up cutting out several studs and reframing quite a bit of the area around the window. This worked well because Aimee and I were rooting for more symmetry with the bedroom window anyway J Now it’s closer to the middle of the wall, and we installed a header to carry the weight of the roof above.

The Master Bedroom window, pre header installation.

As with doors or openings of any kind, it’s important to have the proper structure (ie. a header) installed above to carry the weight of the roof assuming the weight of the roof actually falls on the opening. In my house, one easy way to tell is to look at the roof…duh! On the gable ends, there isn’t really much downward pressure from the weight of the roof – the weight falls on the walls to either side of the gable.

A poorly drawn illustration showing the downward pressure on the walls supporting the "ends" of the roof. Think of laying an open book down on a table..it falls flat. Same with this..there really isn't downward pressure on the gable end of a structure - it's carried by the adjacent walls!

There are other factors to consider when removing and adding structure, but that will get you started!

When actually installing the windows, it's important to have the "hole" properly prepped. There is some debate about whether you should flash the sill before installing the window: one school of thought says yes; another says if the outside of the window is flashed properly, what you do to the sill shouldn't matter. We went with the latter. 

Windows will come stamped with measurements for the openings they will fit into. Assuming you've framed your raw opening to match these measurements, the next thing is to make sure the window unit rests 1/4" above the sill...in the event the flashing we discussed doesn't, in fact, work out, this will help to prevent moisture from hanging around in that opening. Once the unit it centered side-to-side in the opening and leveled up, you're ready to nail the strips to the wall.

Once this is done, take a weather/moisture barrier tape and run a strip across the bottom of the window, over the nail strip. Repeat on the sides, and then the top. This creates a watershed...if water gets behind the siding, it will roll over the tape on the top, down the sides, and over the bottom without getting into the structure of the window and causing rot.
 
Now, I’m off to hang more drywall…I got a ceiling last night!! J