Replacing Aluminum Windows in a 1960s Lynnwood Rambler

If your Lynnwood rambler still has its original aluminum sliders, replacement is almost always the right answer rather than repair. Metal frames conduct cold straight through the wall, which is why they sweat every winter morning, and their rollers, seals and latches are decades past their service life. New vinyl or fiberglass windows go into the same openings, usually in one day, and in an electrically heated home they can earn a Snohomish County PUD rebate.

Why the aluminum sliders in these houses fail together

Lynnwood, Alderwood Manor, Edmonds up the hill and Mountlake Terrace filled in between the 1950s and the 1980s: small ramblers, split-levels and Cape Cods, most of them with horizontal aluminum sliding windows in every room and an aluminum slider to the patio.

Aluminum was cheap, strong and easy to extrude into thin frames. It is also an excellent conductor. On a cold morning the metal frame sits close to the outdoor temperature all the way through, so indoor moisture condenses on it and runs down onto the sill.

Three things follow from that.

• The frame is the weak point, not the glass. Even where a previous owner added storm windows or upgraded the glass, the metal keeps conducting.
• The sills below them take a beating. Years of standing water rots wood sills and stains drywall under the window.
• Everything wears at once. These windows are all the same age, so when the rollers go in one room they are going in the others.

Can you put new glass in an aluminum frame?

Usually not worth doing, and we will tell you so. The frame is what makes the window cold, so new glass in a metal frame leaves the coldest part of the assembly in the wall and the condensation and drafts continue. Original aluminum sliders in a house this age are also often single pane, so there is no insulated unit to replace in the first place.

The exception is a newer metal-clad frame in sound condition with a failed insulated unit. If that frame is thermally broken, glass-only replacement can make sense, and Cory will say so on the visit.

How a new window fits an old aluminum opening

Homeowners often assume aluminum openings need special treatment. Mostly they need honest measuring.

Insert replacement, where the new window fits inside the existing frame, is possible in some aluminum openings and is the wrong call in most of the ones we see. Leaving the metal frame in the wall keeps the cold bridge and shrinks the visible glass twice. On a small bedroom window that is noticeable.

Full-frame replacement, where the aluminum frame comes out down to the rough opening, is the usual recommendation here. It removes the metal, lets us look at the sill and framing where all that condensation has been landing, and lets the new window be flashed properly into the siding. The interior gets new casing and the exterior is sealed back to whatever the house is finished in.

What we will not do is force new trim onto the siding across the whole house because you only wanted part of it replaced. Partial replacements are normal work for us.

The difference between the two methods, and what decides it opening by opening, is covered in insert vs full-frame window replacement.

Style: what these houses take

Ramblers of this era were designed around horizontal glass, and the proportions look right when you keep them.

• Sliders in most openings, replacing like with like. Simple, wide, no crank hardware, and the lowest cost per opening.
• Casements over kitchen counters and in bathrooms, where reaching across to move a sash is awkward, and on the windward wall where the tighter compression seal helps.
• Picture windows where the living room already has one. Keep the width. These houses look wrong when a big front window gets chopped into small units.
• Egress in bedrooms. Older bedroom openings are often short and wide. A slider gives you only half its width as a clear opening, so a casement is sometimes the way to meet the requirement in the same hole. Cory checks that before anything is ordered.

Vinyl handles almost all of these openings, and fiberglass is the upgrade on the big living room glass. Everything we install is on the window replacement page.

The patio slider

The aluminum patio slider is the other unit that fails in these houses, and it is worth quoting alongside the windows. If the frame is sound but the glass is fogged or the door drags, that is a repair. If it is the original aluminum door with a rotted sill, it is coming out. We go symptom by symptom on the sliding glass door page.

Which rebate applies

Lynnwood, Edmonds and Mountlake Terrace are Snohomish County PUD territory. In an electrically heated existing home, PUD pays $100 per window when you are replacing single-pane glass and $50 per window when you are replacing a double-pane frame. The new windows must be double or triple pane rated U-0.30 or lower, and the work has to be done by a PUD-registered contractor. Breeze Free is registered for windows.

That first number is the one that matters in these houses, because original aluminum sliders are commonly single pane. Gas and propane heated homes do not qualify for the PUD program, and glass-only work never qualifies. Details are on the Snohomish PUD rebate page.

Shoreline is the exception in this part of the map. It is in King County and its electricity comes from Seattle City Light, so the PUD rebate does not apply there. A Shoreline home heated primarily by PSE natural gas can qualify for PSE’s window rebate instead.

Amounts and eligibility can change. We confirm the current rules with you before you order.

What Cory looks for

Cory does every estimate himself and he has been putting windows into houses like these for 30 years. In a rambler of this era he checks the sill and framing below each window for the damage all that condensation has been doing, whether the openings have stayed square, what the siding will take, and whether the bedroom windows meet egress. He also tells you which windows can wait, because doing the weather side first and the rest later is a normal plan.

The local picture, city by city, is on our Lynnwood service page.

Questions homeowners ask

Should I replace my aluminum windows or just the glass?

Replace them. The metal frame conducts the cold and causes the condensation, so new glass in the same frame leaves the problem in the wall. The exception is a newer thermally broken frame in sound condition with one failed unit.

Will new windows stop the condensation on my sills?

In most of these houses, yes. Condensation forms where warm indoor air meets a cold surface, and a modern window keeps the interior surface much warmer than bare aluminum does. If the house also has a humidity source such as an unvented bath fan or a wet crawlspace, that needs attention too.

How long does a whole-house window replacement take in a rambler?

A typical rambler with 10 to 14 openings is measured in about an hour, quoted in writing within 48 hours, built in 4 to 6 weeks and installed in one day. Full-frame work on all the openings can run into a second day, and we tell you which yours is when we schedule.

Retire the aluminum sliders

Cory measures every opening, checks the sills for the damage underneath, confirms your heat type for the PUD rebate and gives you a written quote within 48 hours. Ask for a free estimate.