I want to replace a round vinyl window that is the original in our 90's house. Want to replace with like size and shape. What are the steps to work out the R/O for this window, given I can't access it from the outside? Do I just measure the diameter of the opening and add 1"?

The window is about 10' off the floor on the inside and about 40' above grade on the exterior. How do I get the old one out? Do I have to pry out the trim on the exterior? Or do I cut at it from the inside? Thanks in advance.

interior w drywall around exterior w janky trim

1 Answer 1


Its installed by a nailing flange on the outside, it is covered by the window trim. Remove that and you will see the nails holding it in. The window jamb dimension is the outer diameter of the window where it meets the exterior trim, the RO is a 1/2" to 1" bigger than that.

There is a small chance it is held in by nailing tabs, attached to the round jamb and extend into the interior side of the RO. Set with nails in the RO to hold it in place, I seriously doubt this method is used.

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    I'd follow Jack's advice and pull the trim, then the window, to get your dimensions. You can then tack the window back in place while you acquire the new window, or cover the opening with plywood screwed to the framing. It's in a fairly sheltered location, so a bit of rain isn't likely to ruin your day.
    – isherwood
    Mar 22, 2017 at 15:46
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    As for the inconvenient height, this is simply a matter of budgeting for the appropriate scaffolding or lift rental to access it. considering the cost to you and your family of you plummeting 40 feet, don't scrimp on that.
    – Ecnerwal
    Mar 23, 2017 at 1:48

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