Domakihub How to Reglaze a Window: Replace Old Putty Step by Step
Stop draughts and water ingress by removing crumbling glazing compound and sealing your single-pane glass correctly.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 5 min read
Crumbling, shrunken glazing putty is one of the most common causes of draughts and water seeping around window panes in older Greek properties — whether it is a timber-framed villa in the Peloponnese, a holiday rental apartment on the islands, or a traditional hotel with single-glazed sash windows. The repair is straightforward, low-cost, and well within reach of any careful DIYer. The video above walks through the process visually; the steps below give you the full detail and sequence so you can work confidently from start to finish.
Why Glazing Putty Fails in the Greek Climate
Greece's combination of intense summer UV, salt-laden coastal air, and winter humidity cycles is particularly hard on linseed-oil-based glazing compounds. Over five to fifteen years, the oil binders oxidise, the putty shrinks away from the glass or the rebate, and hairline gaps open up. Rain drives into those gaps, softens the underlying timber or corrodes aluminium frames, and the glass itself can work loose over time.
Holiday rentals and hotels face an additional problem: windows are often left closed for weeks or months, allowing heat build-up to accelerate the drying and cracking process. Catching the problem early — when the putty has crazed but not yet fallen away in chunks — makes the job much easier and protects the structural integrity of the frame.
Tools and Materials to Gather Before You Start
You will need a hacking knife or old chisel, a putty knife, medium-grit sandpaper (80–120 grit), a wire brush, linseed-oil glazing putty (sold at any builders' merchant in Greece as στόκος υαλοπινάκων), raw linseed oil or a dedicated primer for bare timber, a small paintbrush, and exterior-grade paint to finish. Wear safety glasses and leather gloves throughout — old putty can be sharp-edged, and glass is unforgiving if a pane shifts unexpectedly.
For aluminium frames, use a non-setting or slow-cure glazing compound rather than traditional linseed putty, as the oil reacts poorly with aluminium oxide. A cartridge-type compound applied with a basic mastic gun gives a neater, longer-lasting result on metal rebates.
Step-by-Step: Reglazing a Single-Pane Window
- 1
Remove the old putty completely
Work around all four sides of the pane with a hacking knife, scoring along the junction between putty and glass. Use a chisel or old screwdriver to lever the compound away from the rebate in sections. Take your time — rushing risks cracking the glass. Once the bulk is gone, rake out any loose fragments with a wire brush. Every trace of the old compound must come out; leaving lumps behind gives the new putty an uneven bed and shortens its lifespan.
- 2
Expose and treat the bare rebate
With the putty cleared, inspect the frame carefully. On timber frames, probe for soft or rotten wood; shallow rot can be stabilised with a wood hardener before you proceed. Brush the clean rebate with raw linseed oil and allow it to soak in for at least 30 minutes — this prevents the dry wood from drawing oil out of the fresh putty too quickly, which would cause premature cracking. On aluminium, wipe the rebate with a solvent (white spirit) to remove grease, then apply the primer specified by your compound manufacturer.
- 3
Apply a thin bed of putty, then seat the glass
Roll a length of putty in your hands until it is pliable and slightly warm. Press a thin, even strip — roughly 3 mm deep — all around the rebate. This is the back-bed layer that cushions the glass. Lower the pane carefully into place, pressing evenly around its perimeter (never in the centre) so the glass sinks into the bed and squeezes out a consistent bead. The pane should sit on small plastic distance packers at the bottom edge to prevent direct contact with the timber. Secure the glass with glazing sprigs (small headless nails) tapped in every 20–25 cm to hold it while the putty cures.
- 4
Apply the face putty and tool a clean bevel
Take another rope of putty and press it firmly into the angle between the glass face and the frame, working from corner to corner without stopping if possible. Use a clean putty knife held at 45 degrees to draw a smooth, angled fillet. The finished bevel should start at the sight-line of the frame and slope down to meet the glass about 2 mm below the inner face of the rebate — this sheds rain rather than holding it. Mitre the corners neatly with the knife tip, and smooth any fingerprints with a brush barely dampened with linseed oil.
- 5
Leave to cure, then prime and paint
Linseed glazing putty needs a minimum of 7–14 days to form a skin before painting, and longer in cool or damp conditions. Do not rush this stage — painting over wet putty seals in moisture and causes peeling within months. Once a firm skin has formed, apply one coat of oil-based primer over the putty and onto the glass by about 2 mm (this bridging coat is the critical weatherseal). Finish with one or two topcoats of exterior gloss in your chosen colour. The paint lap onto the glass is intentional and essential — it is the final barrier against water tracking behind the putty.
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FAQ
- How long does glazing putty last after a proper reglaze?
- A well-applied linseed-oil putty job, properly primed and painted, typically lasts 15–25 years in a temperate climate. In Greece's harsher UV and salt-air conditions, plan to inspect window putty every 8–10 years and touch up any cracks before they open into full gaps. Painting on schedule is the single biggest factor — unpainted putty deteriorates in two to three seasons.
- Can I reglaze aluminium-framed windows the same way?
- The process is similar but the materials differ. Aluminium frames do not absorb linseed oil and the alkalinity of the metal degrades traditional glazing compounds over time. Use a non-setting butyl or polysulfide glazing compound for aluminium, applied from a cartridge. The rebate must be clean and degreased, and the glass should rest on setting blocks as with timber. Some aluminium systems use a dry-glazing gasket rather than compound — if that is the case, replace the gasket rather than applying putty over it.
- Is it safe to reglaze a window without removing the glass?
- Yes, in most cases. If the glass is sound and held securely by the remaining sprigs, there is no need to remove it. Simply rake out the old putty, treat the exposed rebate, and apply fresh compound as described. Only remove the glass if it is cracked, if the frame needs structural repair, or if the sprigs are so corroded they cannot hold the pane during the work. Removing glass unnecessarily adds risk and complexity to what is otherwise a straightforward maintenance task.