Portland has tens of thousands of homes built before 1950, and most of them still have their original double-hung sash windows. Those windows are worth keeping. Here is what the restoration process looks like, what it costs relative to replacement, and when replacement is actually the right call.
What makes original sash windows worth restoring ¶
Old-growth fir and pine, which most pre-1950 sash windows are made from, is denser and more stable than the second-growth lumber used in new wood windows today. The grain is tighter, the wood is harder, and a well-maintained original sash can outlast a new replacement unit by decades. Beyond durability, original sash windows have sight lines and muntin profiles that were designed for the house. Replacing them changes the facade in ways that are difficult and expensive to reverse.
The restoration process in our woodshop ¶
We remove each sash from the frame, bring it to the SE Division woodshop, and assess the condition of the wood, the glazing, and the joinery. Loose joints are re-glued and clamped. Deteriorated wood is consolidated with epoxy filler or replaced with a dutchman patch of matching species. The glazing compound is raked out and replaced. Where the sash depth allows, we install double-pane insulated glass units in place of the original single pane. The sash is then primed, painted, and reinstalled with new weatherstripping and re-roped sash weights.
Energy performance: restored sash vs. Vinyl replacement ¶
A common concern is energy efficiency. A restored sash with double-pane glass and proper weatherstripping performs comparably to a mid-range vinyl replacement window in terms of air infiltration. The difference in U-value is real but smaller than most homeowners expect. The bigger energy losses in most older Portland homes are at the attic floor and the rim joist, not the windows. Spending money on air sealing and insulation typically delivers a better return than replacing windows that are structurally sound.
When replacement is the right answer ¶
We do not restore every window we look at. If the sash is so deteriorated that more than 30 percent of the wood needs replacement, if the frame is racked beyond what shimming can correct, or if the original profile is incompatible with a double-pane unit, we will tell you that replacement makes more sense. In those cases, we specify wood replacement windows with period-appropriate profiles rather than vinyl units that do not fit the original opening correctly.
If you have original sash windows and you are not sure whether to restore or replace, we are happy to take a look. A site visit costs nothing and we will give you a straight answer. Reach out through our contact page to schedule a time.