Rules
Part of Original wood windows compared for value, comfort and long-term fit
Original wood window contractors: how to separate the real ones
How to tell a sash restorer from a replacement window salesperson, using shop questions, sample repairs, drawings and the documentation a review would need.
What to take away
- Ask for a sample repair before signing anything. One restored sash is worth an hour of conversation.
- A restorer talks about joints, rails, putty and cords. A salesperson talks about efficiency ratings.
- Ask for measured drawings of existing and proposed windows. Anyone who cannot produce them has not surveyed your house.
- Lead-safe certification is a yes or no question with a document attached: the firm's EPA Lead-Safe Certified Firm certificate under the Renovation, Repair and Painting (RRP) Rule.
Hiring an original wood windows contractor is not the same business as buying replacement windows, even though both use the same language. Telling the two apart takes about fifteen minutes of the right questions.
Questions that separate the two
- Do you repair sash in place, in a shop, or do you only supply replacements?
- What do you do with a rotted bottom rail? A specific answer names splicing, dutchman repair or a new rail.
- How do you handle sash cords, chains and weights?
- Which glazing compound do you use, and how long before you paint it?
- Can I see a window you repaired more than five years ago?
That last question reveals the most. Repair work should still be sound after five years, and a firm in business a while can offer addresses.
Restorer vs Replacement Salesperson
Restorer
- Estimate method
- Counts and grades each sash
- Pricing basis
- By condition category
- Site inspection
- Looks closely at each window
- Cost changes
- Reconciled before work
Replacement Salesperson
- Estimate method
- Single per-window price
- Pricing basis
- Flat rate across house
- Site inspection
- Nobody looked closely
- Cost changes
- Reconciled later, your cost
The glazing question comes close: the right answer is a waiting period, not a number of hours, and cure times are what actually set a sash schedule. Traditional linseed-oil putty — DAP '33' Glazing Compound off the shelf, or whiting mixed with raw linseed oil in a shop — has to skin over before it is primed and painted. A contractor who promises to prime it the same afternoon is telling you how the rest of the job will go.
Watch how the estimate is produced as well. A restorer counts sash, grades each one, and prices by condition category. A window with two decayed rails is a different job from one that only needs putty and paint.
A single per-window price applied across a whole house usually means nobody looked closely, and it will be reconciled later in your direction. Counting and grading before pricing is how a defensible estimate is built on any old-house job, not a window peculiarity.
Ask for a sample repair
Pay for one window to be done properly before committing to the rest. It settles cost, quality and feasibility in one step, and it converts an argument into evidence.
Reinforcement techniques are worth knowing about because they widen what counts as repairable. The National Park Service's Preservation Tech Note Windows No. 14, Reinforcing Deteriorated Wood Windows, documents methods for stabilizing sash that a general contractor would write off. Preservation Brief 9, The Repair of Historic Wooden Windows, covers the smaller repairs, and both are published by the Park Service's Technical Preservation Services. Bring them to the conversation and see what response you get.
Where to find a restorer
No national registry lists sash restorers, so referrals do the work. Your State Historic Preservation Office and your local historic district commission are the usual first call. The Preservation Trades Network connects craftspeople who work on historic buildings, and the National Trust for Historic Preservation can point you toward local preservation contacts. Better still, ask a preservation architect who has specified window restoration on a real project, and ask any shop you call for addresses you can drive past.
What proper documentation looks like
| Document | Why it matters |
|---|---|
| Window survey with condition grading | Shows the work was actually looked at |
| Measured drawing of an existing sash | Records profile, thickness, muntin width |
| Drawing of any proposed replacement | Lets you compare like with like |
| Photographs of each condition type | Evidence for review, and for you |
| Written method for each repair type | The specification the price is built on |
The federal incentive program asks for essentially this set. The Historic Preservation Tax Incentives program, run by the National Park Service, holds projects to the Secretary of the Interior's Standards for Rehabilitation, and its application — the Historic Preservation Certification Application — asks for the same documentation for a proposed window replacement: clear photographs, measured drawings of existing windows including muntins and meeting rails, and drawings of the proposed replacement at the same scale. Whether or not you are in that program, it is the right standard to hold a contractor to.
Checks that apply to any trade
Verify licensing and insurance from the issuing body — the state or local licensing board that issues the license, and the insurer behind the certificate of insurance. Ask for the EPA Lead-Safe Certified Firm certificate and expect the Renovate Right pamphlet before work starts, get references you can actually visit, and read the payment schedule. The general version of these checks is in our contractor vetting walkthrough, and the technical decision you are hiring against is in our window options compared.
