West Sussex · England
North Mundham Window Mastic
Window mastic for North Mundham and the surrounding area: the right sealant, proper preparation and a neat finish. Call for a quick quote.
- Gaps where the sill meets the wall
- Mastic that has split away from the wall
- Gaps left after new windows were fitted
DIY sealant or a professional job?
A DIY attempt doesn’t rule out a professional job. We cut it out and start again.
If you do try it yourself, take your time over the preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it fails, we can still redo it.
Window mastic in North Mundham, done properly
Frames and walls do not move together. Heat and cold make frames grow and shrink against brick or render that hardly moves. That is why the joint needs a flexible, low-modulus sealant rather than something rigid. We work on timber windows & doors, window sills and aluminium frames, and people most often call us about cracked internal joints between frame and plaster and mastic that’s falling out in pieces.
In a village or hamlet like North Mundham, older cottages and farmhouses often have timber windows set in stone or brick. Older buildings like these don’t always suit modern silicone, and sometimes a traditional sand mastic is the better choice.
We guarantee the work for a year. If there’s a problem with our work within the year, let us know and we’ll sort it.
- Location
- North Mundham (PO20)
- Region
- West Sussex
- Guarantee
- 12 months on all our work
- Quote
- A clear price before we start
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Common questions in North Mundham
Will you come out to North Mundham?
Yes, North Mundham is covered. Our work covers London and the South East, from towns to the smallest places. Longer journeys are simply planned in advance.
Can you help a landlord with a rental near Chichester station?
Yes. We work for landlords and agents as well as homeowners. You can call 0345 464 0079 or email us with the details for a clear quote.
Should I try DIY first?
That depends on the joint. High-level, external movement and fire-rated joints are professional jobs, while a short indoor joint may be within reach.
Is there any odour?
Possibly a little. Any smell clears as the sealant cures.
Do you guarantee window mastic?
Yes. Every job comes with our one-year guarantee, and we’re fully insured.
Can you reach windows above the ground floor?
Generally, yes. Access is planned before any work starts.
Can you do several jobs on one visit?
Yes. Several rooms, windows or areas can go on one quote.
Are you ARBOMaster approved?
Yes. Mr Mastic is an ARBOMaster approved applicator and we are fully insured too.
Places near North Mundham
What else we do in North Mundham
When it isn’t the sealant
A few problems are outside what sealant work can do:
- A frame that has rotted at the joint
- Misting between the panes of a double-glazed unit (that needs a new unit)
- Penetrating damp from a failed cavity tray or render
If you’re not sure, just phone 0345 464 0079 or drop us an email and we’ll give you a straight answer.
Surfaces we seal
- Aluminium frames
- Window sills
- Composite doors
- Patio & French doors
- Timber windows & doors
- uPVC windows
How the job changes by surface
Timber windows & doors
Wood swells when it’s wet and shrinks when it dries, so the joint must stay flexible. We seal onto sound, dry paintwork or timber.
uPVC windows
Plastic frames move a lot between a hot afternoon and a cold night, so the joint needs a low-modulus sealant that stays flexible. We match white, brown, anthracite grey and black frames.
For landlords and businesses
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements and we will quote.
Hotels need rooms back in use, so the work can be planned room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.
Keeping the joints in good condition
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Do not aim a pressure washer at the joints
- Keep paint off silicone joints
- Wash the frames with mild soapy water
- Clear any debris from frame drain holes
On timber frames, keep the paintwork in good order, since wood that gets wet swells and shrinks more. Keep paint off the silicone itself.
Water gets in quietly when mastic fails. Often the first sign is a damp patch inside or flaking paint on the reveal. Early resealing stops it reaching that point.
What we are called out for in North Mundham
Timber windows bring their own problems. Old mastic gets painted over and cracks under the paint, and the wood moves with damp as well as heat.
Keep an eye out for any of the following:
- Leaking joints at the ends of sills
- Rain getting in at the frame or under the sill
- Black, perished sealant on frames
- Rushed sealant from a window installation
In the older streets around The Parish Church of St Stephen, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
Comparing quotes
- How long the guarantee is
- Who does the work, and how experienced they are
- What happens if they find a problem under the old sealant
- What preparation is included
Windows and doors in North Mundham
North Mundham is close to the coast, and homes near the sea take more wind-driven rain, with salt in the air closer to the shore. That is hard on the mastic around window and door frames, especially on the side facing the sea. London and the South East are among the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Rented homes near Chichester station change hands often, and sound mastic around windows and doors keeps out the draughts and damp that tenants notice first. Schools such as North Mundham Primary School are buildings too, and its window and door frames need their mastic kept sound, just like a home’s.
North Mundham is about 2 miles south-east of Chichester, in West Sussex. Anywhere in PO20, our applicators can take on window mastic. North Mundham is one of 371 places in West Sussex where we work. Portsmouth is on our list too, around 14 miles away.
Every address in PO20 is covered for window mastic, from the main roads to the quietest streets. Streets in the area include Church Road, Fletcher Place and Palmer Place, and we cover them all. If you’re just outside North Mundham, we cover Runcton (1 mile east), Hunston (1 mile west), Merston (1 mile east), Donnington (1 mile west) and Lagness (2 miles south-east). Within a short drive, we also cover Bognor Regis (4 miles south-east), Selsey (6 miles south), Littlehampton (10 miles east), Emsworth (8 miles west), Rustington (11 miles east) and Storrington (15 miles north-east).
Around North Mundham
Typical jobs here are in homes near The Spotted Cow Public House and Chichester High School For Girls. The closest station to North Mundham is Chichester station, about 1.6 miles north-west of the centre. A little further out are St Richard's Hospital (2.1 miles north) and Chichester Cathedral Treasury (1.8 miles north-west).
What happens on the day
Before we leave, we go over the finished joints with you. The work normally takes a few hours for a few frames, or a day or more for a whole house, depending on the size of the job. In a small place like North Mundham, access is usually the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- We check each frame and agree which ones need doing.
- Next the failed sealant is cut away and the joint cleaned.
- We fit backing rod in deep gaps so the sealant is the right depth.
- New exterior sealant goes on in a matching colour and is tooled smooth.
- Every joint is checked before we leave.
Before we arrive
- Tell us about any previous sealing or DIY attempts
- Move anything stored near the joints
- Keep pets and children clear of the area while we work
Ask for a quote
It all starts with a short chat. Describe the problem, the location and the size of the job, and we will talk you through what we’d do. Whenever you’re ready, phone 0345 464 0079 or send us an email.