Surrey · England
External Mastic in Green Cross
Specialist external mastic for Green Cross: careful preparation, the right product and tidy work. Call for a quick quote.
- Brick movement joints where the sealant has split
- Sealant that has lost its bond to the brick or render
- Joints pointed up with cement by mistake
External mastic for homes and businesses in Green Cross
Failed sealant is cut out, the depth set with closed-cell backing rod, and the joint resealed with a low-modulus sealant made for outside. The colour is chosen to suit the brick or render. We’re often asked to deal with moss and dirt in joints with no sealant left and leaking joints around cladding and façade panels, on copings & trims, façade panels and brickwork movement joints.
Somewhere as small as Green Cross, homes and farm buildings often face open ground, so walls and rooflines take the full force of wind and rain. Joints on those walls need a sealant that moves with the building and stays in place.
We guarantee the work for a year. If something isn’t right with it in that time, tell us and we will put it right.
- Place
- Green Cross (GU10)
- Wider area
- Surrey
- Cover
- One year on every job
- Quote
- A clear price before work begins
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Common problems we fix in Green Cross
The wrong product in a moving joint is a classic cause. A high-modulus or general-purpose sealant can be too rigid for a busy joint, so it pulls away from the edges.
Look out for any of the following:
- Cracked joints where brick meets render or frames
- Panel joints letting water in
- Brick movement joints where the sealant has split
- Hard, crazed mastic that has stopped moving
If you live in an older home near St John the Evangelist, the joints between older walls, newer extensions and the roofline need a sealant that can move.
What to look for in a quote
- What happens if they find a problem under the old sealant
- What the quote includes, VAT included or not
- Whether you can choose the colour
- Whether the sealant suits the joint
What we do, step by step
There’s no need to move everything out, only the area right around the joints. We protect the rest, and the work takes a few hours to a few days, depending on the length of joint and the access in most cases. In a small place like Green Cross, access is normally the main thing to plan. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- We start by walking round the building and agreeing the joints and the access.
- Every bit of old sealant and any mortar or debris is cut out.
- The faces are brushed clean and primed where the product requires it.
- We fit closed-cell backing rod to control the depth.
- We apply the sealant, tool it and check the whole run.
Before we arrive
- Clear the area around the work
- Tell us about any previous sealing or DIY attempts
- Where the joints are inside, avoid wetting them before we arrive
Ask for a quote
If you’re in Green Cross and need external mastic, phone 0345 464 0079 or drop us an email. Tell us what the problem is and where, and you will get a clear quote before we start.
Related advice
How we quote for external mastic
For a quick quote, just ask. What matters most is:
- The old material and how stubborn it is
- The type of sealant required
- How many areas need sealing
- Any working-time requirements on site
There are no prices on our website, because each job is priced on what it involves. For a quick quote, please phone 0345 464 0079 or send us an email and we will talk you through it.
What to tell us for a quote
What to tell us when you ask for a quote:
- What’s wrong with the joints now
- Any access issues, like height or stairs
- How many joints, rooms or windows are involved
- Any previous sealing or DIY work
For a quick quote, get us on the phone, or email us if that is easier. Describe what needs sealing and we’ll explain what’s involved before giving you a price.
Places near Green Cross
More services for Green Cross
Landlord and commercial work in Green Cross
We also work for property managers and facilities teams. We can quote a run of properties together, and we are fully insured for the work.
Whether it’s one flat or a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
How the job changes by surface
Joints between dissimilar materials
Each side of the joint may need its own preparation. We prepare both faces so the sealant bonds properly.
Brickwork movement joints
Clay brickwork grows slightly over its life and moves with the weather. The movement joint takes that up, so the sealant in it must stay soft and stretchy.
What external mastic looks like in Green Cross
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.
If you let a flat or house near Haslemere station, failed wall and movement joints let damp in, so they’re worth checking between tenancies. Schools such as St John's CofE Aided Infant School are buildings too, and movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Green Cross is about 5 miles south of Farnham, in Surrey. If you need external mastic in Green Cross, please ring 0345 464 0079 or drop us an email for a quick quote. We are based in Crawley and cover Surrey. 395 places in Surrey are on our list, large and small. For nearby work, see our Reading page.
We cover every part of GU10 for external mastic. Neighbouring places we cover for external mastic include Churt (1 mile west), Whitmoor Vale (1 mile south-west), Beacon Hill (1 mile south-east), Barford (1 mile south-west) and Crosswater (1 mile north-west). Further out, we also cover Guildford (11 miles north-east), Woking (15 miles north-east), Camberley (14 miles north), Farnham (5 miles north), Frimley (12 miles north) and Haslemere (4 miles south-east).
Around Green Cross
In Green Cross, that means homes and buildings near Crossways Inn and The Flashes, among other places. The nearest railway station is Haslemere station, roughly 3.7 miles south-east. A little further out are Haslemere and District Hospital (3.8 miles south-east). Green spaces nearby include Gibbet Hill and Farnham Heath.
Why it’s worth doing now in Green Cross
Sealing over the top of old mastic doesn’t hold for long. The new layer cannot bond properly to old, weathered material, so the old joint is cut out fully first. Older cottages and farmhouses around Green Cross can have timber floors and frames, and water through a failed joint can rot timber if it’s left.
Commercial jobs are quoted on the same basis as homes: the amount of work, how we reach it and what it needs, along with when we can work on site. Call for a quick quote and we’ll explain what it covers.
What you get with us
- Sanitary silicone with an anti-fungal additive in wet areas
- Homes, businesses and hotels
- 12-month guarantee on every job
- We never seal over old sealant
Read our cost guide and customer reviews.
Green Cross questions
Can you do external mastic in Green Cross?
Yes, Green Cross is within the area we cover. We work across London and the South East. Just call 0345 464 0079 or drop us an email with a few details of the job, and we will give you a clear price.
Can you help a landlord with a rental near Haslemere station?
Yes. We work for landlords and letting agents as well as homeowners. You can phone 0345 464 0079 or drop us an email with the details for a clear quote.
Can you seal joints between two different materials?
Yes. We cut out the old sealant, prepare both faces and reseal with a flexible exterior product. We pick a colour that works with both materials.
Can I add another job to the visit?
Yes, and it often makes sense. Doing several areas at once is usually more efficient, so mention them when you ask for a quote.
What do you put in the joint?
It depends on the joint: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. Brands we use include Arbo and Everbuild.
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 and reseal when it splits.
Why is there a gap in my brick wall?
A movement joint is a planned break in the wall that absorbs expansion and shrinkage. It should be filled with flexible sealant, never mortar.
Do I need to be at home?
It depends on the job. For work indoors, someone needs to let us in, and for outside work we’ll agree access with you when we book.
Aftercare tips
A little care helps the new joints last. Our advice:
- Walk round the building once a year and look at the joints
- Don’t let climbing plants root in the sealant
- Keep movement joints as flexible joints, not mortar
- Ask before painting over external sealant
Don’t paint over the new sealant unless we’ve said the product is paintable. Paint can crack on a flexible joint and spoil the finish.
An open movement joint lets rain into the wall every time it pours. That can lead to damp patches, staining and frost damage which cost more to put right than the joint.