Medway · England
Lower Upnor External Mastic
External mastic in Lower Upnor from a team with over 20 years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Damp patches traced to an open external joint
- Failed sealant between panels on a façade
- Old sealant gone brittle and cracked
Lower Upnor: your questions answered
Is external mastic in a coastal place like Lower Upnor any different?
Coastal weather is harder on outside sealant: there’s more wind-driven rain and, closer to the shore, salt in the air. Choosing the right sealant for the frame and wall, laid at the right depth, helps it last.
I let a flat near Strood station. Can you help?
Yes, we work for letting agents and landlords. Just ring 0345 464 0079 or drop us an email and tell us about the property, and we will send you a clear quote.
Should I try DIY first?
You can, for simple jobs. Preparation is everything: all the old sealant out, and a clean, dry joint. We can always put it right if it fails.
Where are you based?
We are based in Crawley, West Sussex, and we cover South East England, London and all of Scotland.
What is backing rod for?
That’s backing rod, a closed-cell foam. It stops the sealant going in too deep and bonding to three sides, which would stop it stretching.
Is it OK to seal over old sealant?
No. New silicone will not bond to old silicone, and it traps any mould or water underneath. We remove it all first.
Can you work on commercial sites?
Yes. We work in offices, washrooms, hotels and other commercial premises. Working times can be discussed when we quote.
When will the joints need doing again?
That varies with the weather the wall faces, how much it moves and the sealant used. Treat it as a maintenance item and look at it yearly.
External mastic for homes and businesses in Lower Upnor
Many failed façade joints only get noticed once there’s a stain or a damp patch inside. We look over the joints, agree the ones to renew and reseal with a flexible, weatherproof product in a matching colour. Typical jobs include movement joints with cracked, split or missing sealant and old sealant gone brittle and cracked, across brickwork movement joints, copings & trims and render & cladding joints.
Somewhere as small as Lower Upnor, homes and farm buildings often face open ground, where walls and rooflines take the weather head on. Joints on those walls need a sealant that moves with the building and stays in place.
Whatever the size of the job, it’s backed by our one-year guarantee in Lower Upnor and across Medway.
- Where
- Lower Upnor (ME2)
- Region
- Medway
- Cover
- A year, on every job
- Quote
- A clear price before work begins
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
For landlords and businesses
Housing providers, facilities teams and property managers book us too. Several sites can go on one quote.
From a single let to a portfolio, the work is the same standard: the old material taken out, careful preparation and a 12-month guarantee.
When something else is needed
We’d rather tell you now than do work that won’t last, so here’s what sealant can’t put right:
- Cracks in the bricks or render themselves, away from the joints
- Subsidence or other structural problems
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
Not sure which it is? You can call 0345 464 0079 or drop us an email and we’ll tell you honestly.
Joints and surfaces we work on
- Copings & trims
- Joints between brick and frames
- Render & cladding joints
- Brickwork movement joints
- Concrete & block
- Façade panels
Walls and rooflines in Lower Upnor
Lower Upnor is within about 2 miles of 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 movement joints and outside wall joints, especially on the side facing the sea. Historic houses like Restoration House (about 2 miles south-west) are a reminder that the area around Lower Upnor has older buildings as well as new. Where a home is older, older walls and rooflines need a sealant that moves with them and suits the material.
If you let a flat or house near Strood station, outside joints that have cracked can let damp into a rental, so check them between lets. Managing a site like Chattenden Primary School? Then movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Lower Upnor is about 2 miles north-east of Rochester, in Medway. From the centre of Lower Upnor to the outskirts, we cover external mastic for every kind of property. Across Medway, we cover 68 places, Lower Upnor among them. There’s also a page for Chelmsford, roughly 23 miles from Lower Upnor.
We work across the ME2 postcode area for external mastic and the streets around it. Streets in the area include Galleon Way, Cutter Close and Schooner Walk. Other places close to Lower Upnor include Upper Upnor (1 mile south-west), Chattenden (1 mile north), Wainscott (1 mile west), Hoo St Werburgh (2 miles north-east) and Cooling Street (2 miles north). Larger places within reach include Gillingham (3 miles south-east), Chatham (4 miles south), Rainham (5 miles south-east), Strood (3 miles south-west), Luton (3 miles south) and Park Wood (5 miles south-east).
Landmarks near Lower Upnor
Around Lower Upnor, our work takes us to homes and buildings near Former Ordnance Store At Chatham Gun Wharf, The Hundred of Hoo Academy and Waterfront University Technical College. Also close by are Lower Lines Park (1.3 miles south-east) and The Ship pub (under half a mile east). For rail, the closest station is Strood station, roughly 1.6 miles south-west of the centre. A little further out are Upnor Castle (within half a mile south) and Pentagon Shopping Centre (1.9 miles south). The countryside around Lower Upnor includes Rede Common and Gad's Hill.
The process
Before we leave, we go over the finished joints with you and explain the cure time. The visit itself generally takes anything from a few hours to several days, depending on the building, depending on the size of the job. In a small place like Lower Upnor, access is normally the main thing to plan. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- We look at every joint and agree a colour to suit the wall.
- We take out the old sealant until the faces are sound.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- Primer is applied wherever the sealant needs it.
- We gun in low-modulus sealant and tool it neatly.
How to prepare
- Tell us about any previous sealing or DIY attempts
- Plan for the work area to be out of bounds to pets and children
- Mention any sign-in or site rules at work premises
Ask for a quote
We quote each job on its own, so the first step is telling us about yours. Just ring 0345 464 0079 or email us with the details.
Related advice
How the job changes by surface
Concrete and blockwork
Wide joints in concrete need the depth controlling carefully. Backing rod sized to the joint sets it.
Copings and trims
Metal and stone copings both move with temperature, so a flexible sealant suits them best in all weathers.
How to look after the new joints
Looking after new joints is easy, and it makes a real difference:
- Keep soil, plants and ivy away from the joints
- Ask before painting over external sealant
- Act on the first splits you see
- Fix overflowing gutters above sealed joints
Don’t let soil, plants or ivy build up against the new joints. Anything that holds water against the joint wears it out sooner.
Small splits are the time to act. At that stage it’s a simple cut out and reseal before water has had years to get in.
Places near Lower Upnor
What else we do in Lower Upnor
Should I try it myself first?
If you are set on DIY, put the effort into 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.
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions, and the work is guaranteed for a year.
Do you need external mastic in Lower Upnor?
A lot of failed joints come down to preparation: dusty or wet faces, no primer where one was needed, or old sealant left in. The new sealant then lets go long before it should.
It’s worth asking for a quote if you see:
- Rain getting behind render or cladding at a joint
- Plants rooting in failed movement joints
- Movement joints filled with mortar instead of sealant
- Panel joints letting water in
For an older house near a landmark such as St Philip & St James, an extension built onto an older house moves differently, and the joint between them takes the strain.
Before booking anyone
- Is VAT in the price?
- When the joint can take water or movement
- Whether you can choose the colour
- What happens if the job turns out different