Deventer Profielen

Quick Facts

Brand at a Glance

Product Range

Why This System

Step 1 of 2: Manufacturer Recommendations

Official Care Guidance

Glass

• ✓Lukewarm water with mild soap. Keep solution away from the rubber compression seal perimeter - solution that sits against the seal during the wash phase degrades the seal surface over repeated applications.
• ✓Squeegee solution away from the seal line where possible. Direct the squeegee bead toward the drainage slot, not toward the seal.
• ✓After squeegeeing, wipe the glass edge near the glazing gasket with a barely damp cloth. Do not push moisture into the junction between the glass edge and the gasket.
• ✓No solvent-based glass cleaners. No ammonia-based cleaners. Both attack EPDM and TPE seal materials.

Frames

• ✓Wipe frame faces with damp cloth and pH-neutral cleaner. Rinse thoroughly - residue left on the frame near the seal groove attracts grime that sits against the seal between cleans.
• ✓On the seal itself, wipe gently with a barely damp cloth if the seal surface is visibly dirty. Do not scrub. Do not apply cleaning product directly to the seal.
• ✓Check the seal groove at the frame perimeter - particularly at the corners where the seal is most likely to have lifted or pulled away. A seal that is not seated fully in the groove needs to be pressed back in - do this by hand, not with a tool.
• ✓No bleach, chlorine, or solvent products on or near any seal. The most common source of seal damage on PVC installations is bleach used on the frame surface dripping onto the adjacent compression seal.

Hardware

• ✓Hardware maintenance is separate from seal maintenance but related - stiff or poorly adjusted hardware causes the sash to compress unevenly against the perimeter seal, loading some seal sections more than others. Keep hardware lubricated to ensure even sash compression.
• ✓On doors with Deventer automatic drop seals, clean the threshold contact surface - the floor or threshold bar that the drop seal compresses against - at every visit. Grit on the contact surface wears the seal lip faster than normal operation.
• ✓Check that the drop seal on entrance doors extends and retracts smoothly. Grit or debris in the seal mechanism prevents full extension and leaves a gap at the door bottom when closed.

Step 2 of 2: The Orloffs Protocol

The Orloffs Protocol

Pro Tools

My daily tool list. This is what I carry to every job.

Follow these steps in order. Each one builds on the last. This is the same sequence I use on every Deventer Profielen installation.

1. 1

   Seal inspection before washing

   Before any water touches the window, inspect the perimeter compression seal on each window. Look for sections where the seal has lifted from the groove, flat spots where compression has failed, cracks in the rubber surface, and missing sections at corners.

   Check the glazing gaskets at the glass edge. Gaskets that are pulling away from the glass or the rebate face need to be flagged before cleaning begins.

   On entrance doors, check the drop seal extension. Open the door and observe the drop seal mechanism - it should extend fully when the door closes and retract fully when the door opens.

2. 2

   Glass wash

   Apply solution to the glass with controlled T-bar strokes. Keep the T-bar cover away from the compression seal at the sash perimeter - the cover picks up rubber particles from aged seals and deposits them on the glass.

   On windows with exposed EPDM seals (common on aluminium systems), the seal is visible on the front face of the sash. Keep the T-bar strictly on the glass and off the seal face.

   Work in panels - complete the full glass wash on one window before moving to the next. This reduces the time solution sits against the seal perimeter.

3. 3

   Edge detail

   Before squeegeeing, wipe the glass edge near the glazing gasket with a barely damp cloth. Do not push the cloth into the glass-to-gasket junction.

   On the compression seal face, if the seal is very dirty, wipe gently with a barely damp cloth at this stage. Do not apply cleaning product to the seal directly.

   Wipe the top frame rail and the seal section at the top of the sash dry before squeegeeing - drips from the top during the pull pass down over the compression seal on the sash sides.

4. 4

   Squeegee

   Direct the squeegee bead toward the bottom of the glass and away from the compression seal at the sash sides. On a side-to-side squeegee technique, angle the rubber slightly so the bead falls toward the centre and down rather than toward the frame edge.

   The final bottom squeegee pass: direct the bead toward the frame drainage slot and away from the compression seal at the bottom of the sash.

   Wipe the rubber dry after every pass. Solution transferred from the rubber onto the seal surface during the squeegee pass is the most common source of product residue accumulating on EPDM seals.

5. 5

   Frame and seal wipe-down

   Wipe all frame faces with pH-neutral cleaner on a damp cloth. Rinse with clean water. Dry the frame surface near the seal groove - do not leave moisture sitting in the groove alongside the seal.

   On the seal itself, a final gentle wipe with a barely damp cloth is sufficient. Do not use frame cleaner on the seal surface - rinse water only.

   On entrance doors, clean the threshold channel and the floor contact surface for the drop seal. Use a soft brush and rinse with clean water. Dry the contact surface before operating the door.

6. 6

   Seal condition report

   After cleaning, do a final seal inspection. Compare what you see now with the pre-clean inspection. Note any sections where the seal has moved or where cleaning has revealed damage that was hidden by grime.

   On doors with drop seals, operate the door through a full close-and-open cycle after the threshold is clean and dry. Confirm the drop seal extends and retracts smoothly.

   Flag any seal issues to the owner in writing. A compression seal that is flat, cracked, or lifting is not a cleaning problem - it is a maintenance problem that affects the window's thermal and weather performance.

Pro Tips

• ★ The most useful tool for EPDM seal maintenance is a dedicated seal conditioner applied once per year after cleaning. It restores flexibility and significantly extends service life beyond what cleaning alone achieves.
• ★ Compression seals that are flat at the corners but still functional in the straight sections have usually been over-compressed by a sash that is adjusted too tight - flag this as a hardware adjustment issue, not a seal replacement issue.
• ★ On aluminium windows with exposed EPDM seals on the sash front face, the seal is the most visible maintenance indicator on the whole window. A grey, chalky EPDM surface is a sign of UV degradation or solvent exposure - not dirty glass.
• ★ Deventer drop seals on entrance doors are adjustable - the descent depth can be set to match floor level. If a drop seal is leaving a gap at the door bottom, it may need adjustment rather than replacement.
• ★ On PVC installations where the compression seal is recessed in the frame groove, it is easy to miss during cleaning. Run a finger along the seal groove after the frame wipe to feel for grit or residue that was not removed by the cloth.
• ★ In cold weather, EPDM seals become stiffer and less compressible - windows that seemed to close properly in summer may admit a draught in winter. This is a hardware adjustment issue, not a seal failure.
• ★ Keep a note of seal condition at each visit. A seal that changes condition significantly between two visits - faster than normal weathering would explain - indicates that something is attacking it between cleans.

What NOT To Do

Bundle Kits and Tool Recommendations

Cleaning Frequency

Glass: 2x per year minimum (Spring and autumn. The seal inspection at each glass clean is as important as the glass cleaning itself.). Seal inspection: Every clean (Visual check of all compression seals, glazing gaskets, and door seals at every visit.). Seal conditioning: Once per year (EPDM-compatible conditioner applied after the annual autumn clean.). Drop seal adjustment: As needed (Check drop seal descent depth annually or when a draught is reported at the door bottom.)

Frequently Asked Questions

Field Notes

“The most useful observation a professional cleaner can make on a Deventer-sealed window is seal condition at the corners - corners are where seals lift first, and lifted corner seals are invisible to the owner but obvious to a trained eye. On Dutch and Belgian residential windows, Deventer seals are ubiquitous - if you work in the Benelux market, you are working with Deventer seals on most of your jobs whether you know it or not. Automatic drop seal maintenance on premium entrance doors is a professional service almost never included in a standard cleaning contract - it takes five minutes and saves seal replacement costs.”

Justin Orloff