Official Technical Guide

uPVC Door
Installation Guide

A complete step-by-step guide for the safe, secure and professional fitting of your House of Windows uPVC door.

📞 Need help? Call us: 01530 515161 | 💬 WhatsApp: 07427 935161 | ✉ sales@houseofwindows.co.uk
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Read Before You Begin

All goods are checked before leaving our factory.

Do not begin installation if you find any damage or incorrect sizing. All shortages or damages must be reported to House of Windows within 48 hours of delivery.

Over 90% of remedial work is caused by incorrect installation — follow this guide carefully. If unsure at any stage, consult a qualified installer.

Contents
1Before You Begin 2Safety & Compliance 3Pre-Installation Checklist 4Tools & Materials 5Measuring & Preparation 6Cill Fitting 7Frame Installation 8Glazing & Toe and Heeling 9Hinge Adjustment 10Sealing & Insulation 11Final Checks 12Troubleshooting 13Aftercare & Maintenance
01
Section

Before You Begin

🚫
Do not remove your old door until you have:

Inspected the new unit for damage · Confirmed the new frame is ~10mm smaller than your aperture on all sides · Verified all components are present (handles, cill, glass, fixings) · Tested door operation — lay the frame flat horizontally to test sash operation

✅ Storage

Store frames and glass units vertically on soft surfaces such as wooden blocks or carpet. Keep indoors and away from direct sunlight.

✅ Protective Film

Remove protective film from the inside of the frame before installation. Leave the outside film on until all external sealing is complete.

❌ Sharp Edges

Never lean frames against metal, brickwork or other sharp surfaces — these can permanently damage uPVC profiles and glazing seals.

❌ Direct Sunlight

Do not leave any uPVC door panels in direct sunlight. Prolonged heat causes thermal distortion and the protective film will bond to the surface.

02
Section

Safety & Compliance

👥
Two People
Always use two people for lifting, positioning and glazing. Never attempt solo installation.
🪜
Working at Height
Use stable, weight-rated platforms or ladders. Never stand on makeshift surfaces.
🧤
Gloves
Wear cut-resistant gloves when handling glass at all times.
🥽
Eye Protection
Wear safety goggles when drilling into masonry.
🥾
Footwear
Steel toe-capped footwear is recommended throughout installation.
03
Section

Pre-Installation Checklist

Complete every item on this list before beginning physical installation. Rushing this stage is the single most common cause of remedial work.

  • Measure the brick opening width in three places (top, middle, bottom) — note the smallest measurement
  • Measure the brick opening height in three places (left, centre, right) — note the smallest measurement
  • Measure both diagonals — they should be equal; a difference >2mm indicates an out-of-square opening requiring correction
  • Verify the floor level is consistent across the full width of the opening
  • Confirm a suitable, load-bearing lintel is in place above the aperture
  • Confirm the new frame is approximately 10mm smaller than the aperture on all sides
  • All components present: handles, cill, glass units, fixings, packers, end caps
  • Remove protective film from the inside of the frame
  • Remove all old frame debris, sealant residue and masonry dust from the opening
04
Section

Tools & Materials

Tools Required

📏
Spirit Level
Long (1.2m+)
🔩
Power Drill
+ Masonry bits
🔨
Rubber Mallet
For glazing beads
🔧
Allen Keys
4mm & 5mm
📐
Tape Measure
5m minimum
🔫
Sealant Gun
For silicone
🪣
Glazing Paddle
Plastic type
📦
Frame Packers
Assorted 1–6mm

Materials

MaterialSpecificationStatus
Frame Fixers7.5mm × 120mm minimumRequired
Glazing PackersAssorted 1mm–6mm thicknessRequired
Silicone SealantLow-modulus neutral cure siliconeRequired
Cill Fixing Screws50mm self-tapping screwsRequired
Expanding FoamLow-expansion PU foam (for gaps >10mm)Optional
uPVC Flexi-TrimTo cover foam/silicone edgesOptional
05
Section

Measuring & Preparation

📏
The 10mm Rule

Your new uPVC frame should be approximately 10mm smaller than the brick aperture on all four sides. This allows for the mandatory 5mm expansion gap on each side, plus room for packing and adjustment.

BRICK APERTURE uPVC FRAME 5mm GAP EACH SIDE DIAGONALS = EQUAL ×3
5mm
Mandatory expansion gap on every side
~10mm
Frame smaller than aperture each side
<2mm
Max diagonal difference — opening is square
0mm
Floor must be perfectly level
💡
Out-of-Square Openings

If the brick opening diagonals are unequal, do not attempt to force the frame into a distorted shape. Use packers strategically to keep the new frame perfectly rectangular even if the surrounding brickwork is not.

06
Section

Cill Fitting

  • Size & Cut: Cills are supplied with a 50mm horn on either side. Cut to the width of the brick opening, or leave oversized for a projected sill finish.
  • Sealing: Apply a generous, continuous bead of low-modulus silicone to the top face of the cill where the frame will sit. This creates a weathertight seal between the cill and frame.
  • Fixing: Screw the cill to the bottom of the frame using 50mm self-tapping screws. Position the first screw 150mm from each end, then space fixings no more than 500mm apart along the length.
  • End Caps: Apply silicone to the inside of the end caps and push firmly onto each horn. This prevents water from tracking behind the cill and into the brickwork.
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End Cap Sealant Is Critical

Never leave end caps unfitted or unsealed. Water that tracks behind the cill into the wall cavity can cause significant structural damp that is costly to repair.

07
Section

Frame Installation

A

Preparation — Remove Sashes & Pre-Fix Panels

Optionally remove the door sashes from the frame to reduce overall weight before offering up into the opening. Pre-fix any side panels to the main frame before positioning.

ℹ️
Side Panel H-Section

Place the 20mm aluminium H-section between the door frame and side panel — it should fit snug but not clip. Screw through the door frame into the side panel using 70mm self-tapping screws, alternating screw positions for maximum rigidity.

B

Positioning — Offer Frame Into the Opening

With at least two people, carefully offer the frame into the brick opening. Support the bottom with timber wedges at the sill corners. Position centrally within the reveal, front to back. Do not fix yet — this is a positioning step only. Ensure the cill silicone is still wet.

C

Levelling — Plumb, Level & Square the Frame

This is the most critical step. Take as long as necessary to achieve a perfectly plumb, level and square frame before any fixings are inserted.

  • Check the sill is level across its full width — adjust packers to correct
  • Check the hinge-side jamb is plumb — pack behind the frame as required
  • Check the lock-side jamb is also plumb
  • Check the frame head is level — adjust corner packers if needed
  • Measure both frame diagonals to confirm squareness (within 2mm)
  • Place packers at all four corners and at the mid-point of each jamb
D

Fixing — Secure Frame to Masonry

Drill through the frame into the masonry and secure with frame fixers. Follow these fixing positions precisely:

  • Place fixings 150mm from each corner of the frame
  • Maximum 300mm apart vertically along each jamb
  • Security critical: On the locking side, place a fixing as close as possible to the multipoint lock keep
  • Fix the hinge side first, re-checking plumb after each fixing
  • Do not over-tighten — excessive torque will bow the frame
  • Always fix through packers — never into an unsupported void

Minimum Fixing Depth by Substrate

Brick / Block
≥ 50mm
Concrete
≥ 40mm
Timber Frame
≥ 60mm
08
Section

Glazing & Toe and Heeling

🚨
Toe and Heeling Is Non-Negotiable

uPVC doors are heavy. Without correct toe and heeling, the door leaf will sag over time, causing it to fail to lock and creating draughts. If a service call is requested and the door is found not to have been toe and heeled, charges will be incurred.

TOE HEEL HINGE SIDE HANDLE SIDE GLASS = DIAGONAL BRACE
Step 1 — Toe

Insert glazing packers into the bottom corner on the hinge side (the "Toe") before the glass is inserted.

Step 2 — Insert Glass

Carefully lower the glass unit into the frame rebate, sitting it onto the toe packers.

Step 3 — Heel

Use a glazing paddle to lift the handle side. Insert packers into the top handle-side corner (the "Heel").

Step 4 — Fit Beads

Snap glazing beads back in using a rubber mallet — short pieces first, then long. Soapy water spray helps stiff beads seat.

💡
Stubborn Glazing Beads?

If beads are difficult to snap into place, a light spray of soapy water (washing-up liquid diluted in water) applied to the bead edge will lubricate it without causing damage.

09
Section

Hinge Adjustment

House of Windows uPVC doors use Flag Hinges with three independent adjustment points, allowing fine-tuning in all axes without removing the door. Use a 4mm or 5mm Allen key for all adjustments.

↕️
Bottom of Hinge

Vertical / Height

Turn clockwise to raise the door, counter-clockwise to lower. Adjust in small increments, checking after each turn.

↔️
Side of Hinge

Lateral / Side-to-Side

Move the door leaf closer to or further from the frame. Corrects misalignment between master and slave door that causes the lock to fail.

🔧
Front / Top of Hinge

Compression

Pull the door tighter against the weatherseal to eliminate draughts. Adjust equally on all hinges for an even seal around the full perimeter.

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Need More Help?

For a detailed hinge adjustment guide, visit our Technical & Downloads section or call us on 01530 515161.

10
Section

Sealing & Insulation

  • Internal seal: Use a low-modulus silicone or acrylic decorator's caulk to seal the gap between the frame and internal plasterwork. Smooth with a wetted finger for a clean finish.
  • External seal: Wipe down both the brickwork and uPVC frame with a clean cloth to remove dust and grease. Apply a bead of high-quality exterior-grade perimeter sealant around the full outside perimeter of the frame.
  • Large gaps (>10mm): Fill with low-expansion polyurethane foam first. Allow to fully cure (minimum 2 hours), trim flush with a sharp knife, then apply silicone sealant over the trimmed foam surface.
  • Remove outside film: Only remove the external protective film from the uPVC profiles once all external sealing is complete.
🚨
Use Low-Expansion Foam Only

High-expansion polyurethane foam exerts significant pressure as it cures and will bow and distort uPVC frames, making doors impossible to close or lock. Always use low-expansion foam around uPVC installations.

11
Section

Final Checks

  • Open and close both doors — they should move smoothly and freely without catching, scraping or requiring force at any point
  • Check all locking points (hooks and bolts) on the multipoint lock fully engage when the door is closed and handle lifted
  • Inspect the drainage slots in the bottom of the frame — clear any debris, foam residue or silicone blocking these slots
  • Verify the handle operates the multipoint lock without binding — the mechanism should feel smooth throughout its full travel
  • Check the door compresses evenly against the weatherseal around the full perimeter — no visible gaps
  • Remove all temporary packers, wedges and bracing used during installation
  • Remove the external protective film from all frame profiles
  • Wipe down all uPVC surfaces with a clean, damp cloth — do not use solvents
12
Section

Troubleshooting Guide

⚠️ Door catching or dragging at the bottom
Cause: The door has "dropped" — toe and heeling was not completed correctly, or has shifted over time.
Fix: Redo the toe and heeling process, or adjust door height using the vertical adjustment on the hinges (Allen key, bottom of hinge).
⚠️ Lock won't engage / hooks miss the keeps
Cause: The master and slave doors are misaligned horizontally relative to each other.
Fix: Adjust the lateral hinge screws (side of hinge) to move the affected door leaf until the lock points align.
⚠️ Draughts felt around the door
Cause: Insufficient compression against the weatherseal, or the weatherseal has been flattened or trapped.
Fix: Check compression adjustment on all hinges. Inspect the full perimeter weathergasket for damage, flattening or trapped sections.
⚠️ Frame bowing inward after foam curing
Cause: High-expansion foam was used instead of low-expansion foam.
Fix: Remove the foam, repack correctly, and replace with low-expansion foam. Add rigid packers at the affected area before re-foaming.
💡
Still having issues?

Our technical support team is available Mon–Fri 9am–5.30pm. Call 01530 515161 or WhatsApp 07427 935161.

13
Section

Aftercare & Maintenance

Every 6 Months
  • Wash uPVC frames with warm soapy water and a soft cloth
  • Spray multipoint lock with light machine oil or lithium grease
  • Oil all hinges with light machine oil
  • Wipe weatherseal gaskets with a damp cloth to keep supple
  • Check drainage slots in the frame base are clear
Annually
  • Inspect all external sealant beads — re-apply if cracked or debonded
  • Check frame fixings have not loosened — re-tighten gently if required
  • Inspect glazing seals for failure (condensation between panes)
  • Re-check door alignment and adjust hinges as needed
As Needed
  • Replace worn or damaged weatherseal gaskets
  • Replace failed glazing units — contact House of Windows
  • Lubricate door cylinder with graphite-based lubricant (not oil)
  • Replace damaged glazing packers if door begins to sag
⚠️
Do Not Use WD-40 for Long-Term Lubrication

WD-40 is a water displacer, not a lubricant. It will dry out the lock mechanism and cause increased wear over time. Use light machine oil or white lithium grease for the lock and hinges. For the door cylinder, use graphite-based lubricant only — oil-based products attract grit and will damage the cylinder.

🚫
Never Use Solvents on uPVC

Never use white spirit, methylated spirits, acetone, bleach, abrasive creams or scouring pads on uPVC profiles. These will permanently discolour and damage the surface. Use only warm soapy water or a specialist uPVC cleaner.

Need Help or a New Door?

Our team is here Mon–Fri 9am–5.30pm · sales@houseofwindows.co.uk

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