aside from getting the wrong size windows,what are some of the more common problems contractors are confronted with when replacing windows? rotted wood>? where is wood usually rotted? rooted frame??ect...
same question but with patio doors?

 

If done right, sizing is never an issue. For new construction windows, the trim must be removed to expose the framing, then measure the RO. For replacement windows, it requires 8 measurements, top-bottom-middle vertically and horizontally, and check the corners for square. And the window depth, usually 3 1/2"for replacements, 4 9/16 for new, but can be different. The smallest dimension is the opening size, distributors will take either opening size or make size. For opening size, they reduce by 1/4". Make size is just what is says, that is the size they will make the window.

Rot is sometimes a problem when the old windows were junk or poorly maintained. How much repairs are done depends on the extent of the damage. Termites are sometimes an issue, because it is usually unexpected.

Make sure you fill all air gaps around the windows, I use DAP foam, it won't push out framing as expanding foam can do. For old windows with weight pockets, fill the pockets with fiberglass, loosely but full. Packed fiberglass does not insulate well.

Follow manufacturers directions. Failure to do so could void their warranty.

 

in older homes,is it most likely frame damge(jamb)? 2x4 need to be replaced? how bout headers and sills?

 

It would help to know if you're doing this replacement style or new construction.

If it's replacement style - no one is going to see (or CARE to see) any of the framing. Either way it's rarely a problem.

The patio door is a different story. It is a great time to take a good hard look at the floor for moisture etc. I would suggest that you are there to supervise, and not have someone who's in a hurry cover up an existing problem.

 

Good point by Mac. Patio doors are notorious for leaking to the framing, and need to be checked carefully before installing a new door.

 

Some problems I've run into through the years:

1. Aluminum Frame removal-always a treat
2. Fixed panels-- sometimes they can be interesting to remove without breaking--deglaze the glass sometimes helps.
3. Bugs--Ants and bees sometimes make their home inside your wall cavities.
4. Windows painted shut-this ones easy to remedy.
5. New unit has manufacturer defect. Sometimes very tricky to spot what is wrong.
6. Existing opening not square--In extreme cases you may have to order your window smaller to compensate.
7. Removal of old unit-especially with awnings, sliders and casements, may require lots of chiseling.
8. Placement of new unit--Sometimes there are no outside or inside stops. Pick a place that will be easy to install new stops.
9. No J channel outside--run a saw between siding and exterior casing/brickmold to slide your metal into, if your capping the exteriors.
10. Location-window in a vaulted great room, and walkout basement outside.
11. Location- Patio door on deck upstairs off master bedroom with no outside access-how to get unit to location.
12. I could go on for hours.