A rough opening is quite simply the opening in a wall where a door or window will be placed. For windows in particular, the rough opening must be prepared in such a way to spread the load the wall is bearing coming from the roof. This is to make up for the fact that the normal spacing of studs is interrupted to accommodate the width of the window. When framing a wall for windows, the width of the rough opening will be left basically equal to the outside dimensions of the window for both height and width.
Included in this measurement is the jamb, and a half inch is added in both directions to account for margin of error and to promote ease in plumbing and leveling the window unit when it is installed. Shims are used to tighten back up the rough opening cavity and prevent the picture window from moving around once it is in place. Without shims, if the window is simply nailed or screwed into place it could slowly come loose from normal usage of opening and closing the window, and eventually cause the window to perform poorly or possibly even to fall out.
Installing Vinyl Replacement Windows
When installing replacement windows, the rough opening dimensions will be clearly marked on the packaging. Once the old window has been removed and the home replacement windows are ready to be installed the rough opening can be inspected. Check the dimensions against those on the picture window replacements packaging. Make sure the dimensions are correct and make adjustments if necessary.
Inspecting a Rough Opening
This is also the time to repair the rough opening if it should be necessary to do so. There are a few important things to look for when inspecting a rough opening prior to replacing windows. When you replace windows, part of the reason usually has something to do with function. This is the time to make sure that there is nothing about the rough opening or the wall that will impede function of the vinyl window replacements.
Make sure the wood is in good condition and that the size of the rough opening is correct. You need good wood to be able to attach to in order to ensure that the new window installation holds and that it does not go anywhere over time. Do not count on the interior trim to hold the window into place. Be sure the fasteners used are of sufficient length and width to hold the weight of the window and to sink adequately into the rough opening.
Considering Replacement Windows Cost
The preparatory work you may have to do on the rough openings of older homes especially should be figured into the expected cost of the job. If there have been longstanding leak issues with the existing windows, it is highly likely that the wood comprising the rough opening is rotted, especially in first story units. Also be sure to check any insulation in these cases, because it can be full of mold and may need to be replaced. In certain cases a window replacement job may also require the removal of some drywall to get at the wood and the insulation and repair it all correctly. Hopefully this will not be the case all around the house, because this can get expensive very quickly.
The rough opening needs to be framed correctly and in good condition in order to hold up new windows. Anyone spending the money to replace their house windows should make sure to attend to this detail to ensure a long lasting job.