2. The ceiling beams above must be supported
during the construction. 
Proper installation of all windows and doors 
includes a header and jack studs on either side. 
This assembly transfers the weight from the 
structure above, sort of around the window, 
and transfers the weight to the floor below.
When you make the opening larger, the existing
header must be removed, and a new header inserted
between the studs in the outer wall, and new jack
studs inserted to transfer the weight supported by
the longer header, again to the floor.
While you are removing the old header and installing
the new one, the beams in the ceiling above need to
be supported. You can do this with a 2x4 minimum,
spanning a greater width than the new window or
door, held up snug by 2x4’s as shown. Do this as
close to the outside wall as is practical.
3. Carefully 
re-establish 
the water 
management
system in the
wall.
The new window
or door will be
exposed to more
outside weather,
and if it is a
door, then 
the sill will be
subject to 
water intrusion
if it is not 
properly crafted.
Study the
installation 
procedures 
for Bay, Bow
and Garden
windows and
entry and patio
doors for the
steps needed 
to create a 
proper water
management system for the newly added unit. Once
you are adding a new header and support framing,
the techniques for new construction will apply.
The good news is that when making the opening 
bigger, finishing the exterior siding and trim and the
interior wallboard and molding is simpler because
the pieces you might remove are not destroyed and
should be able to be trimmed to size and reused.
Window Fitters Guide to Window Installation
124                  Contents ©2022-Do not reproduce without permission
SAMPLE MANUAL

View this content as a flipbook by clicking here.