Measuring RO for a Picture Window

I want to replace the single pane wooden picture window in my living room with a vinyl replacement window.
I just want to check my measuring method before I call the dealer.
I pulled the inside trim so I can see the rough opening on the sides and top. However, I can't see the bottom of the RO because of the interior sill. The side-to-side RO measures 48".
For the height, I slipped a thin strip of metal between the bottom frame and the sill (in three places) until it bottomed out, marked it and measured it: 1 3/16".
I then added this to the measurement from the top of the rough opening down to the interior sill (52 7/8") for a total of 54 1/16".
So, as far as I can tell, the measurements to call in are 48" w x 54 1/16" h.
Now, I also took these measurements:
The wooden frame on the bottom of the window *outside* the house, where I can see the entire frame, right down to the sill: 2 7/8".
The exposed wooden frame on the bottom of the window inside the house: 1 5/16".
If I add the exposed portion on the interior (1 5/16") to the hidden section on the interior (1 3/16") I get 2 1/2".
That's 2 1/2" inside, 2 7/8" outside.
Is it safe to assume that the "extra" 3/8" on the outside is due to the slanted sill and that the existing wooden window is slanted on the bottom to match the sill? (The "thickness" of the frame is ~1 1/4")
I also assume that the VRW will not have a slanted bottom and that I should ignore that extra 3/8" when I call in the measurements. The exterior gap can then be covered with trim or with an expander strip that should come with the window.
So, the correct measurement is the interior measurement of 48" w x 54 1/16" h right?
Thanks!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Different manufacturers measure the rough opening of a bay window in different ways. Call the manufacturer and ask them to send you a cut sheet that shows exactly where the rough opening is measure from. Then draw up a sketch showing exactly what you have and where your measurements were taken from, and send that to them.
A number of manufacturers have outside salesmen who make the rounds. Request one stop by next time he's in the area to measure for you and pick up the deposit check. They love hearing that last part. The first part takes the onus off of you for any mis-measurements.
R
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

neat idea!!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 10/09/11 6:25 PM, RicodJour wrote:

It's not a bay window, it's a picture window - just a large flat window.

This window will be a Simonton window, purchased through a Norandex-Reynolds dealer, just like all the other windows that I've purchased and installed over the past couple of years.
The counter guy that I work with said to measure the RO, just like I measured the RO for all the other windows. The only difference is that the other windows were double hungs, so I had access to the top and bottom of the RO opening once the sashes were out of the way. (i.e. open)
Since I can't open the picture window, I don't have access to the bottom sill area.

I'm not sure if this option is available...it wasn't offered when I purchased the other windows. The only option that was "offered" was that if I was afraid to take my own measurements I could hire a contractor to come over and measure for me. I opted out of that "offer", did my own measurements and (luckily?) got all 14 of them correct.
The "kitchen casement replaced with a slider" was the most challenging, not because of the measurements, but because the trim work wasn't just an R&R like the other windows.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Oops. Sorry about that, Chief! Missed it by _that_ much!
Hang on a second...okay, I just reread your original post, and this time with full comprehension!
First thing I do in sizing up any remodeling project is start poking holes. They don't have to be big. You're going to be pulling the window right? Drill a hole or two and poke a piece of wire coat hanger in the sill to see where the framing is.
R
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Clarify if you're going to put the VRW inside the existing frame work of the window. Using the term RO, usually means stud to stud etc.
Also, VRW do usually have slanted sills on the exterior. It is common to take a sawzall and cut the existing sill flush on the exterior. You then cap the exterior off, sliding the capping under the VRW. The VRW should/will have a trim piece to snap into place on the bottom, assuring elements will not enter between the capping & window.
When I used to order VRW's, I would take measurements for width in 3 places (top, center, bottom). Take the smallest of the measurements, then minus 1/2". This allows you room for out of square openings. When taking the height, take 3 measurements again, using the same method. Sometimes windows do not come with header expanders, make sure you specify you want it. You can always shim the window up, which is common. You do not want a tight fit, expansion will crack the glass once the weather changes. Allowing room for being out of square, also allows you to fill the gaps with insulation.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Forget to mention, when you order, make sure you tell them HOLD TO SIZE! Otherwise, you may find out you get a smaller window then what you wanted.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 10/09/11 6:41 PM, Eddie wrote:

Existing Framework.
As far as I can tell from pulling the interior trim and exposing the "pocket" (which is the word the salesman used - "Measure the pocket") the new window will be the same size as the existing window and slip right into the pocket.
Since there are no interior stops, it appears that to remove the window, I first need to remove the aluminum frame for the storm, then remove the exterior stops and the window should be able to be removed from the outside.
The new window should slip into the pocket in the same manner - I hope!

I don't believe that the double hungs I replaced had slanted sills. If I recall correctly, the bottom of the windows were flat and cut to fit the smallest measurement - right at the interior sill. The snap-in trim piece you mentioned below was included to fill the gap.

I'm not sure what you are referring to here. I didn't cut anything when I installed my 14 double-hungs and I can't even imagine what I would have cut. My sills are wrapped in aluminum, which extends right up to the interior sill.

As I said in my OP:
"For the height, I slipped a thin strip of metal between the bottom frame and the sill *(in three places)* until it bottomed out, marked it and measured it"
Those three places were right, left center.

When I ordered my double-hungs, they wanted the full RO measurement and they took care of the subtraction. All windows fit perfectly, with room for shims and a nice small gap for caulking, so I'll trust their judgment this time also.

I don't like the look of header expanders, either on the interior or exterior. I chose to shim the windows up for a cleaner look at the top of the window. I plan to do the same thing for the picture window.

I agree.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.