North West Domestic · UK Commercial
External Sealant across Liverpool, Wirral, Cheshire & the North West.
External mastic for façades, brick, render, cladding and window perimeters across the North West and nationwide for commercial work. Old sealant is removed and the cause of any water ingress is assessed before resealing.
- Clean, Precision Trade Workmanship
- 5.0★ on Google (54 Verified Reviews)
- Old Grout & Sealant Always Removed First
- 100% In-House Trained Specialists
External Sealant
Precision Finish
Trade Grade5.0 / 5 on Google
54 reviews · Rated "Great price"
Old Sealant Removed
Stripped back & cleaned first
5-Year Guarantee
Workmanship & adhesion guarantee
Fair & Fixed Price
Quick quote by phone or message
Site Qualifications & Accreditations
Certified for domestic homes, commercial sites, powered access and high-rise rope access
Who You Are Dealing With
Deal directly with Liam.From first quote to finished job.
No call centres. No subcontracted strangers. From your first WhatsApp photo quote to the final tooled bead of silicone, Director Liam Harrison oversees your job personally. For specialist tile restoration, Liam works alongside family craftsmen with over 22 years on the tools—ensuring every joint is immaculate.
Liam
· Lead Mastic Specialist · 8 Years ExperienceYour direct point of contact from quote to completion
22+ Years Trade Experience
· Grouting & ResealingTrusted family & senior specialists on the tools alongside Liam
Certified & Fully Insured
· Domestic & CommercialCSCS Gold, SSSTS, IPAF, PASMA, IRATA & NVQ L3 · £5m/£10m insured
Liam · Next Level Sealants
Silicone & Regrouting
UK Commercial Sites“Friendly, tidy and clearly takes a huge amount of pride in his work.”
See how colour-matched silicone looks on your surfaces.
1. Tap What You Need Sealing:
Tap any area to test surfaces & colours
Scope of Work
External Work We Carry Out
External joint seals are your building's primary shield against driving rain, frost, wind, and draughts. When exterior window or façade mastic splits, shrinks, or peels away, rainwater tracks directly into cavity insulation, rotting timber sub-frames and creating damp, bubbling paint around internal window reveals. Led by Liam, our specialist team mechanically extracts all weathered mastic, brush-cleans the masonry reveal, inserts closed-cell polyethylene backing rod to prevent three-point adhesion failure, and tools high-performance low-modulus neutral cure silicone or MS polymer weatherseals engineered for 15 to 20 years of UK weather exposure.
- External window and door frame perimeter sealing01
- Brick, render, and stone interface movement joints02
- Cladding and architectural panel joints03
- Thresholds, steps, and sub-cill weather-laps04
- Closed-cell backing rod installed to prevent centre splitting05
- Low-modulus neutral cure silicone & MS polymer systems06
- 100% old weathered sealant mechanically extracted07
- Draught-proofing and water ingress protection08
When to Call Us
Common Problems We Fix
Cracked, split, or shrinking external window mastic
01Solar UV radiation, winter freezing, and frame expansion cause cheap builder's mastic to shrink and split down the centre. We rake out the failed material and reseal with flexible, low-modulus neutral cure silicone rated for ±25% joint movement.
Damp window reveals and bubbling interior paint
02Rainwater entering through unbonded exterior mastic tracks through the cavity, soaking internal plaster reveals and blowing interior decor. Resealing from the exterior face stops the water ingress at the building's true weather line.
Cold draughts and whistling wind around frames
03Ruptured exterior perimeter seals allow cold air to bypass window frames, driving up winter heating bills. Our airtight elastomeric perimeter seals restore building envelope efficiency.
Cladding panel and expansion joint leaks
04Commercial cladding panels expand heavily in summer sun. We install high-performance ISO 11600 Class 25LM weatherseals and backing rods to absorb thermal sway without tearing.
Our Process
How We Do the Job
Elevation Inspection & Defect Diagnosis
We examine the joints to identify adhesion failure, movement stresses, backing void depth, and safe access requirements.
Full Mechanical Extraction & Surface Clean
Failed existing mastic is raked out down to bare frame and masonry. The reveal is wire-brushed clean and wiped with fast-flashing solvent degreasers.
Backing Rod Insertion (2:1 Ratio)
Oversized closed-cell polyethylene foam backing rod is compressed into deep voids to enforce the correct 2:1 width-to-depth joint ratio and prevent three-sided adhesion tearing.
Tooling Weather-Lap Sealant Profile
Commercial low-modulus neutral cure silicone or MS polymer is extruded and shaped with a downward weather-lap profile that actively sheds driving rainwater.
Proof of Work
Completed Projects
Genuine examples of our sealant and mastic work across the North West and the UK.
Marks & Spencer, Speke Retail Park
Internal and external mastic package for the new Marks & Spencer at Speke Retail Park, including external windows, doors, wall joints, internal movement joints, pillars and the rear service yard.
Everton Stadium
Mastic and sealant package for the new Everton FC stadium at Bramley-Moore Dock.
Aintree Racecourse
Internal and external sealant package on Aintree Racecourse's multi-million pound renovation, including the Jockeys' Changing Room, commercial wet rooms, hospitality areas and external window perimeters.
Specialist Options
Related Services
Façade & Cladding Repairs
For larger commercial façade and cladding joint resealing, see our dedicated façade and cladding service.
Rope Access Mastic
High-level or difficult-access external joints can be reached through our UK-wide rope-access mastic service where appropriate.
FAQ
Common Questions
Have another question about your job? Send a photo on WhatsApp or use our quote form and we will help straight away.
Can you reseal around existing windows without removing them?+
Yes, absolutely. We replace the exterior perimeter mastic around existing UPVC, aluminium, and timber frames without disturbing or removing the window units.
Does failed external mastic cause damp inside around windows?+
Yes. Failed external mastic is one of the leading causes of damp window reveals, peeling paint, and mould growth around frames. Water enters the perimeter gap and tracks through the cavity wall to the internal plasterboard.
Can you put new external mastic over old mastic?+
No, never. New silicone will not adhere to dirty, weathered, or mouldy silicone. A 'capping' bead will peel away within months. All old sealant must be raked out to clean, bare substrate before resealing.
What is the best mastic for external windows and doors?+
A low-modulus neutral cure silicone (such as Dowsil 791 or SikaHyflex) or an MS polymer hybrid is best. They offer high movement accommodation (±25%), superior UV and weather resistance, and non-corrosive adhesion to UPVC, aluminium, timber, and brick.
How do I get a fixed quote for external window resealing?+
Send 2 or 3 photos showing your external window and door frames along with your postcode to Liam on WhatsApp. We provide a guaranteed fixed price before booking.
More Services
Related Services
North West & Nationwide UK
Commercial Mastic
Subcontract commercial mastic and joint sealing packages across Greater Manchester, Liverpool, Cheshire, and nationwide. CITB SSSTS supervision, CSCS skilled cards, £10m liability insurance, and zero-defect first-time handover sign-offs for main contractors and QSs.
View ServiceStructural Movement Joint Sealing
Expansion Joints
Movement joint sealing for commercial and industrial buildings. The sealant is selected to suit the joint, with backing rod and primer where the system requires it.
View ServiceSealant Removal, Repair & Renewal Across the North West
Repairs & Resealing
Old, mouldy, split, or peeling sealant stripped out completely and replaced across Liverpool, St Helens, Warrington, Wigan, the Wirral and the North West. We mechanically remove 100% of failed mastic, sterilise joints with industrial biocides, and install trade-grade silicone backed by our 5-Year Domestic Guarantee.
View ServiceWhere We Work
Areas We Cover for External Sealant
Based in Liverpool, we cover Merseyside, the Wirral and the North West daily, with nationwide UK coverage for commercial and construction mastic packages.
Every Domestic Reseal Backed by Our 5-Year Guarantee.
We do not cap fresh silicone over old sealant. Because we cut out all failed material, solvent clean the joint and apply professional trade silicone, our sealant stays bonded. If it ever fails under normal domestic use, we return and replace it 100% free of charge.
Applies to all domestic bathroom, shower, kitchen, window, door, and floor perimeter silicone resealing (excludes rigid cementitious tile grout). Commercial projects carry standard 12-month DLP.
Why Next Level Can Guarantee Adhesion
Most handymen charge £50 to pump fresh silicone over mouldy old beads in 15 minutes. It peels in 3 months.
Full Mechanical Strip-Out
Every failed millimeter is removed right back to bare tile, acrylic, and frame.
Solvent Degreasing & Dry Prep
Silicone can only bond to chemically clean surfaces. We scrub soap scum and dry completely.
Pure Low-Shrinkage Silicones
Trade cartridges with active fungicides that flex with movement without splitting.
Ready When You Are
Get a Quote
Send photos and your postcode by WhatsApp, email or the contact form and we will come back with a price.
How your quote works
- 1Send photos2 or 3 photos of the job plus your postcode on WhatsApp
- 2Get a fixed priceExact all-inclusive quote agreed before you book — no callout fees
- 3We do the work100% strip-out, tidy finish, backed by our 5-year guarantee
“Great service no mess and and really professional job would definitely recommend them”
Online Quote Request