Hampshire · England
Sleaford External Mastic
Movement joints in Sleaford need attention? We remove the old material, prepare the joints and seal them properly.
- Joints where the bead has come unstuck
- Damp patches traced to an open external joint
- Failed seals between different materials
External mastic in Sleaford, done properly
Short cuts in external joints show up within a season or two. Overfilled joints, missing backing rod and sealant laid over old sealant rarely last long. We strip the joint back and start again. We work on render & cladding joints, concrete & block and joints between brick and frames, and the jobs we see most are water getting into walls through failed joints and rigid filler in a joint that should flex.
Around Sleaford, older buildings can be stone, brick or timber-framed, many with extensions added later. The joints where those materials meet are the weak points.
Every job comes with a one-year guarantee.
- Place
- Sleaford (GU35)
- Wider area
- Hampshire
- Cover
- 12 months on all our work
- Price
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
What affects the cost of external mastic
You will get a clear quote before work begins. It takes into account:
- How easy the joints are to reach
- How much there is to do
- Mould in or behind the old joints
- How many rooms, windows or areas are involved
Doing several joints on one visit generally makes better use of the time than several visits. You’ll get one clear quote for the whole job.
Asking for a quote
Before you ask for a quote, have a think about:
- What’s wrong with the joints now
- How we’d reach the joints
- The type of property
- The address or postcode of the job
For a quote, call 0345 464 0079 or send us an email with the location and a short description of the problem. We’ll give you a clear price before any work starts.
More services for Sleaford
How the job changes by surface
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.
Joints between dissimilar materials
Joints where frames, sills or panels meet the wall are common leak points. The old joint is removed and a sealant that bonds to both sides goes in.
Leave it or put it right?
Water gets in through a failed movement joint, behind render and cladding. Resealing early keeps the job to the joint itself, instead of the wall and finishes around it. In a small place like Sleaford, homes can be exposed to wind and rain, which finds any gap, and damp in older walls is slow to dry out.
Every job is a little different, so each one gets its own quote. Size, access and the product the joint needs all play a part.
What you get with us
- Experience in homes, commercial sites and hotels
- 180+ five-star Google reviews
- We are fully insured
- ARBOMaster approved applicator
Take a look at what affects the cost and what customers say.
Work for landlords, hotels and businesses
We work for landlords and agents as well as householders. Resealing between tenancies is a simple way to keep a property in good order.
If you manage several properties in or around Sleaford, several properties can go on one quote. Send us the addresses and the work at each, and photos by email help.
Looking after it afterwards
How long the joints last depends on use and care. We suggest:
- Point out the joints to other trades
- Get split or bare joints resealed while the damage is small
- Never let anyone fill a movement joint with mortar
- Fix overflowing gutters above sealed joints
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.
Water getting behind cladding or render can go unnoticed for a long time. By the time there’s a damp patch, the damage can be well established.
What we cannot put right
Before you book, it’s worth knowing the limits:
- Walls that need new movement joints cut into them
- Cracks in the bricks or render themselves, away from the joints
- Rising or penetrating damp from elsewhere in the wall
If you’re not sure, just phone 0345 464 0079 or send us an email and we will give you a straight answer before you book.
What we seal
- Concrete & block
- Joints between brick and frames
- Copings & trims
- Brickwork movement joints
- Façade panels
- Render & cladding joints
What happens on the day
You don’t need to clear the whole room or building, only the area right around the joints. Everything nearby is protected, and the job takes a few hours for a handful of joints, longer for a whole elevation for a typical job. Somewhere like Sleaford needs a little journey planning: let us know about lanes, gates and parking. We bring what the job needs, so it can be finished in one trip where possible.
- We start by walking round the building and agreeing the joints and the access.
- We cut out the old mastic and rake out anything in the joint.
- Joint faces are cleaned back and primed if the sealant needs it.
- Backing rod sized to the joint goes in to set the depth.
- The exterior sealant is applied, tooled and checked along its length.
Preparing for the visit
- Try not to wet indoor joints just before the visit
- Mention any leaks or damp you’ve noticed
- Tell us about any previous sealing or DIY attempts
Get a quote
If you’re in Sleaford and need external mastic, ring 0345 464 0079 or send us an email. A short description of the job and where it is helps us quote, and you’ll get a clear quote before any work starts.
Related advice
Sleaford questions
Do you work for landlords with property near Bentley (Hampshire) station?
Yes, landlords and agents are among the people we work for. You can ring 0345 464 0079 or email us with the details for a clear quote.
Is Sleaford in your area for external mastic?
Yes, Sleaford is within the area we cover. We work across London and the South East. You can call 0345 464 0079 or email us and let us know what needs doing.
Should I point up the gap in my brickwork?
No. Rigid materials cannot move with the wall and the joint fails. If it has already been filled, we can normally cut it out and reseal it.
Why do you put foam in the joint first?
That’s backing rod, a closed-cell foam. It keeps the sealant at the right depth and bonded to the sides only, which would stop it stretching.
Can you work on commercial sites?
Yes, regularly. We can plan bigger jobs in stages to suit the site.
Do I have to be there?
It depends on the job. For work indoors, someone needs to let us in.
When is the sealant fully cured?
It depends on the product and the temperature. Before we leave, we’ll tell you the cure time.
Can you quote for more than one area?
Of course. Doing several areas at once is usually more efficient.
External mastic in Sleaford: local notes
Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
If you let a flat or house near Bentley (Hampshire) station, split movement joints are easy to miss on a rental until damp shows inside. Schools such as Mill Chase Academy are buildings too, and larger buildings have long runs of movement joint that eventually need resealing. If you live in an older home near Church of All Saints, older walls, gutters and the joints where extensions meet them need a flexible sealant.
Sleaford is about 5 miles east of Alton, in Hampshire. We provide external mastic to homeowners, landlords and businesses in Sleaford. Our Hampshire coverage runs to 683 places, Sleaford among them. For nearby work, see our Reading page, about 22 miles away.
Our applicators cover all of GU35 for external mastic. Close by, we work in Kingsley (1 mile west), Pinewood Village (1 mile south), Lindford (1 mile south), Frithend (1 mile north) and Bordon (2 miles south). Further out, we also cover Basingstoke (14 miles north-west), Farnborough (12 miles north), Fleet (10 miles north), Aldershot (9 miles north-east), Alton (5 miles west) and Petersfield (10 miles south).
Around Sleaford
In Sleaford, that means homes and buildings near The New Inn, among other places. For rail, the closest station is Bentley (Hampshire) station, roughly 3.2 miles north. A little further out are Chase Community Hospital (2.1 miles south). Not far away are Deadwater Valley.