Hampshire · England
Southwood External Mastic
Problem with your movement joints in Southwood? We remove the old material, prepare the joints and seal them properly.
- Rain getting behind render or cladding at a joint
- Joints pointed up with cement by mistake
- Joints with sealant missing in places
Aftercare tips
So the new joints stay in good condition:
- Wash walls gently around the sealant
- Walk round the building once a year and look at the joints
- Keep movement joints as flexible joints, not mortar
- Check the sealant is paintable before painting near it
If you have more work done on the wall, such as new render, cladding or an opening, show the contractor the movement joints. They must stay as flexible joints, never rendered or pointed over.
Act while the splits are small. Then it’s a straightforward cut-out and reseal before water has had years to get in.
External mastic in Southwood
Movement joints let brickwork, render and cladding expand and shrink without cracking. Its sealant has to flex with the building, season after season, and when it fails, the wall takes the strain and water finds a way in. Common call-outs are for movement joints filled with mortar instead of sealant and old sealant gone brittle and cracked, on concrete & block, copings & trims and render & cladding joints.
In and around Southwood, older properties sit alongside newer ones, each with its own outside joints. Older gutters and trims need their joints resealed; newer brick and render need their movement joints kept sound.
A one-year guarantee comes as standard.
- Location
- Southwood (GU14, GU51)
- Wider area
- Hampshire
- Guarantee
- One year on every job
- Quotes
- Quoted before any work starts
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Nearby places to Southwood
Other services in Southwood
Why deal with it now?
Pointing a movement joint with mortar might seem a neat fix, but it stops the joint moving. The wall then cracks somewhere else. The correct repair is a flexible sealant with the right backing. Around Southwood, water from a failed joint in an older home can soak into timber and plaster, and that’s a much bigger job than renewing the sealant.
Doing several joints on one visit generally makes better use of the time than several visits. You will get one clear quote for the whole job.
Why us?
- ARBOMaster approved applicator
- Arbo and Everbuild products
- White, clear, grey or another colour, product permitting
- Tidy, careful work
See what affects the cost and customer reviews.
When it isn’t the sealant
To be straight with you, there are a few things sealant won’t fix:
- Cracking across the wall rather than at a joint
- Subsidence or other structural problems
- Failed render or damaged cladding panels
If you’re not sure, just call 0345 464 0079 or email us and we will give you a straight answer.
Surfaces we seal
- Façade panels
- Copings & trims
- Joints between brick and frames
- Brickwork movement joints
- Concrete & block
- Render & cladding joints
DIY versus a professional finish
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.
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.
The process
On the day, we start by going over the job with you. We protect the surfaces around the joints before we start. The work generally takes a few hours for a handful of joints, longer for a whole elevation. A visit to Southwood is planned like any other: the time, the access and where to park are agreed in advance. If the work is outside, the weather plays a part, as sealant needs a dry surface.
- We start by checking each joint, agreeing the ones to redo and how we’ll reach them.
- Old sealant and any debris are cut and raked out.
- The joint faces are cleaned and primed where the sealant needs it.
- Closed-cell backing rod is fitted to set the depth and stop three-sided bonding.
- A flexible exterior sealant is applied and tooled in a colour to suit the wall.
How to prepare
- Try not to wet indoor joints just before the visit
- Let us know about earlier repairs to the joints
- Mention any leaks or damp you’ve noticed
Ask for a quote
For a quote, ring 0345 464 0079 or email us with the location and a short description of the problem. We will give you a clear quote before any work starts.
Read more
What affects the cost of external mastic
Every job gets its own quote. This is what makes a difference:
- The old material and how stubborn it is
- Access and height
- Any working-time requirements on site
- The size of the job
Leaving a failed joint generally makes the job bigger, not smaller, because water and mould keep working on it. If you’re not sure whether it needs doing, call 0345 464 0079 or send us an email for an honest opinion and a quote.
Asking for a quote
What to tell us when you ask for a quote:
- If someone has resealed it before
- Access, such as stairs, a lift or height
- The address or postcode of the job
- Photos by email, if that’s easy
Call for a quick quote, or send an email if you’d rather. Describe what needs sealing and we will explain what’s involved before giving you a price.
Common questions in Southwood
Is Southwood within the area you cover?
Yes, we do. Our work covers London and the South East, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
Do you cover Southwood for external mastic?
Yes, Southwood is within the area we cover. Our work covers London and the South East. You can call 0345 464 0079 or drop us an email and tell us what needs doing, and we will give you a clear price.
Is it messy?
Tidy work is part of the job. We protect what’s around the joints.
Can you seal joints between two different materials?
Yes. Materials like render, brick, metal and uPVC all move differently, so the joint between them must be flexible. We choose one that suits both surfaces.
How long will you be here?
That depends on the amount of work, but most jobs take a few hours to a few days, depending on the length of joint and the access. We will give you a better idea when we quote.
Can you do several jobs on one visit?
Yes, we can. Several rooms, windows or areas can go on one quote.
I rent my home. Can I book you?
Yes, though it’s best to check with your landlord first. Landlords are often happy for the work to be arranged.
Can you seal over the old sealant?
No, and we never do. It can look neat for a few weeks, but the new layer lifts away from the old one. The old sealant has to come out completely.
What external mastic looks like in Southwood
The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
Letting a property close to Fleet station? Then failed wall and movement joints let damp in, so they’re worth checking between tenancies. For an older house near a landmark such as St John the Baptist, older walls, gutters and the joints where extensions meet them need a flexible sealant. Schools such as Southwood Infant School are buildings too, and larger buildings have long runs of movement joint that eventually need resealing.
Southwood is about 1 mile west of Farnborough, in Hampshire. For external mastic in and around Southwood, please call 0345 464 0079 or drop us an email for a quick quote. We cover Hampshire from our Crawley base, Southwood included. 683 places in Hampshire are on our list, from the larger towns to small villages. There’s also a page for Reading, about 13 miles away.
Postcode districts we cover here for external mastic: GU14 and GU51. Whether your property is on Fleet Road, Kennels Lane and Summit Avenue or a nearby road, our applicators can take on the job. Nearby, we also carry out external mastic in Cove (1 mile north), Farnborough (1 mile east), North Camp (2 miles east), Mytchett (3 miles east) and Aldershot (3 miles south-east). Further out, we also cover Basingstoke (13 miles west), Alton (12 miles south-west), Yateley (4 miles north-west), Bordon (13 miles south), Hook (7 miles west) and Popley (12 miles west).
What’s near Southwood
In Southwood, that means homes and buildings near National Aerospace Library, Ancells Farm Park and Cove School and the streets around them. Southwood’s nearest station is Fleet station, roughly 1.5 miles west of the centre. Well-known places in the area include Hart Shopping Centre (2.1 miles west) and Royal Army Dental Corps Historical Museum (2.6 miles south-east). Green spaces nearby include Aunt's Pool and Ball Hill.
Different surfaces, different methods
Concrete and blockwork
Wide joints in concrete need the depth controlling carefully. We size the backing rod to the gap so the sealant is not too deep.
Cladding and façade panels
Panel systems often rely on sealant between and around the panels. Each joint gets a sealant that suits the panel and its movement.