Greater London · England
Window & door mastic in Penge, Greater London
Professional window mastic in and around Penge, with every bit of old sealant taken out first.
- Whistling draughts around closed windows
- Water coming in at the bottom corners of a door
- Untidy mastic left by window fitters
How we handle window mastic in Penge
Over two decades of sealing frames has taught us which products suit which walls. We are ARBOMaster approved and fully insured, and we give a one-year guarantee on the work. If you have water coming in at the bottom corners of a door and old mastic that has gone black or come away, we can help, on window sills, aluminium frames and uPVC windows alike.
London has a lot of flats and conversions, where windows are often on upper floors. Who looks after the outside of the frames can depend on the lease, so check that first.
The work is covered for a year after we finish. If there’s a problem with it, please call 0345 464 0079 or send us an email.
- Place
- Penge (SE20, SE19, SE26)
- Region
- Greater London
- Guarantee
- One year on every job
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
What sealant work can’t fix
To be straight with you, there are a few things sealant won’t fix:
- A door that needs adjusting, rehanging or new seals
- Rotten timber, which needs a joiner first
- Damp problems in the wall away from the window
Not sure which it is? You can call 0345 464 0079 or email us and we’ll tell you honestly before booking.
What we seal
- uPVC windows
- Composite doors
- Patio & French doors
- Window sills
- Timber windows & doors
- Aluminium frames
How the job changes by surface
uPVC windows
Fitters’ mastic on plastic frames is sometimes thin and rushed. We cut it out, back any deep gaps and reseal properly.
Patio & French doors
Not every patio door leak is a mastic problem: worn seals, blocked drainage slots or a poor threshold detail can be the cause. We check before we reseal.
DIY versus a professional finish
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
What we do, step by step
Every visit runs the same way: we check the joints, mask and protect the surrounding surfaces, carry out the job and clear up. Most jobs take a morning for a couple of windows and a door. For a job in Penge, parking and access are the things to plan: let us know about parking, the floor we will be working on and any lift or shared entrance.
- First, we go round the frames with you and agree the list.
- We remove the old mastic and clean the frame edge and wall.
- Where the gap is deep, backing rod goes in first.
- A flexible exterior sealant is applied in a colour to suit the frame.
- Every joint is tooled smooth and checked before we leave.
Preparing for the visit
- Tell us about any previous sealing or DIY attempts
- Tell us about access, such as stairs, a lift or high-level joints
- Mention any leaks or damp you’ve noticed
Getting a quote
Quotes start with a quick conversation. Describe the problem, the location and the size of the job, and we’ll talk you through what we’d do. Whenever you are ready, ring 0345 464 0079 or drop us an email.
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Frames and glazing around Penge
Historic houses like Kingswood House (about 1.4 miles north-west) are a reminder that the area around Penge has older buildings as well as new. Where a home is older, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic. Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
If you let a flat or house near Penge West station, cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets. Schools such as Harris Primary Academy Crystal Palace are buildings too, and its window and door frames need their mastic kept sound, just like a home’s.
Penge is about 1 mile west of Beckenham, in Greater London. If you need window mastic in Penge, it’s easy to get a quote: please call 0345 464 0079 or drop us an email. We’re based in Crawley and cover Greater London. Our Greater London coverage runs to 764 places, Penge among them. London is on our list too, about 6 miles from Penge.
Here we cover the SE20, SE19 and SE26 postcode area for window mastic. That includes homes and businesses on High Street, Anerley Station Road and Station Road and the roads around them. Penge sits on or near the A234. Other places close to Penge include Anerley (1 mile west), Crystal Palace (1 mile north-west), Sydenham (1 mile north), Gipsy Hill (1 mile north-west) and Upper Norwood (1 mile west). Larger places within reach include London (6 miles north), City of Westminster (8 miles north-west), Marylebone (8 miles north-west), Kensington (8 miles north-west), St Pancras (8 miles north) and Shoreditch (8 miles north).
What’s near Penge
In Penge, that means homes and buildings near Crystal Palace School, Crooked Billet pub and Crystal Palace Dinosaurs. There’s a railway station in Penge itself: Penge West station. Other landmarks nearby include St Christopher's Hospice (0.5 miles north) and Crystal Palace Museum (0.8 miles north-west). Not far away are Dulwich Upper Wood and Knight's Hill.
What else we do in Penge
What we’re called out for in Penge
Every frame moves through the day. Sun on a frame makes it expand, and it contracts again overnight, while the masonry beside it stays put. If the sealant can’t stretch, it splits.
Keep an eye out for these signs:
- Draughty joints inside around the window
- Whistling draughts around closed windows
- Rushed sealant from a window installation
- Leaking joints at the ends of sills
If you live in an older home near Church of St John the Evangelist, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Before booking anyone
- What the cure time is
- Whether VAT is included
- Whether you can choose the colour
- How long the guarantee is
How we quote for window mastic
For a quick quote, just ask. What matters most is:
- The number of rooms or windows
- Working hours on commercial sites
- Mould in or behind the old joints
- The type of sealant required
Homes and businesses are quoted the same way: the amount of work, the access and the products needed, plus any working-time requirements on site. Call for a quick quote and we’ll explain what it covers.
Helping us quote
There’s no need for technical detail. Just tell us:
- Where the property is
- If it’s domestic, commercial or a hotel
- What the problem is, such as mould, gaps, leaks or cracking
- Any access issues, like height or stairs
Want a quote for window mastic? Please ring 0345 464 0079 or drop us an email and tell us about the job. You will know what we plan to do, and what it will cost, before any work begins.
Landlords, agents and businesses in Penge
Letting agents often deal with us directly. Tell us the address, the job and how access works and we’ll give you a quote.
Hotels need rooms back in use, so we plan the work room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.
Questions from Penge
Can you do window mastic in Penge?
Yes, Penge is within the area we cover. We work across London and the South East. You can phone 0345 464 0079 or send us an email and tell us what needs doing, and we’ll give you a clear quote.
Can you help a landlord with a rental near Penge West station?
Yes, we work for landlords and letting agents. Just ring 0345 464 0079 or email us and tell us about the property, and we’ll send you a clear quote.
What should I tell you?
Just the basics: the address or postcode, what’s wrong and any access issues. Then call 0345 464 0079 or send us an email.
Do you take out the old sealant first?
Yes. All of the old material is cut out and the joint cleaned.
Where is Mr Mastic based?
Our base is in Crawley, West Sussex, and we cover South East England, London and all of Scotland.
Are you fully insured?
Yes. Full insurance covers our work.
Can you quote for more than one area?
Yes, we can. Several rooms, windows or areas can go on one quote.
Can you seal over the old sealant?
No, it will not last. It may look fine at first, but the new layer lifts away from the old one. The old sealant has to come out completely.