Hertfordshire · England
External & façade joints in Colney Street, Hertfordshire
Professional external mastic in and around Colney Street, with every bit of old sealant taken out first.
- Damp patches traced to an open external joint
- Sealant that has lost its bond to the brick or render
- Weathered mastic that no longer stretches
External mastic for homes and businesses in Colney Street
Joints between dissimilar materials, like brick against render or concrete against a steel frame, see movement from both sides. A flexible sealant bridges the two where mortar or filler would crack. If you have hard, crazed mastic that has stopped moving and water getting into walls through failed joints, we can help.
Around Colney Street, older buildings can be stone, brick or timber-framed, many with extensions added later. Where one material meets another is where water usually gets in.
All our work comes with a one-year guarantee, wherever you are in Hertfordshire.
- Location
- Colney Street (AL2, WD7)
- Wider area
- Hertfordshire
- Guarantee
- One year on every job
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Quotes for external mastic in Colney Street
Every job gets its own quote. This is what makes a difference:
- Which sealant suits the joint
- The size of the job
- Any working-time requirements on site
- How many areas need sealing
A failed joint rarely gets cheaper to fix by waiting. If you are unsure, ring 0345 464 0079 or drop us an email and we’ll give you an honest view and a quote.
What we need to know
Before you ask for a quote, have a think about:
- A few photos by email, if you can
- Roughly how big the job is
- If someone has resealed it before
- The problem you’ve noticed
Every job is quoted individually, so start by telling us what you need. Just phone 0345 464 0079 or send us an email with the details and send photos if you have them.
Aftercare tips
Once the sealant has cured, a few habits help it last:
- Walk round the building once a year and look at the joints
- Point out the joints to other trades
- Never let anyone fill a movement joint with mortar
- Act on the first splits you see
Look over the joints once a year, ideally after winter. Watch for splits, edges coming away or growth in the joint.
Once a joint can’t move, the wall finds another way, often as cracks near the joint. Catch it early and you reduce the risk.
External mastic in Colney Street: local notes
With historic houses such as High Elms Manor (about 2.9 miles west) nearby, there’s older building stock in the area around Colney Street as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material. 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.
For site and facilities teams at buildings such as Park Street Church of England Voluntary Aided Primary School, larger buildings have long runs of movement joint that eventually need resealing. For an older house near a landmark such as Church of the Holy Trinity, an extension built onto an older house moves differently, and the joint between them takes the strain. Rented homes near How Wood station change hands often, and failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Colney Street is about 3 miles south of St Albans, in Hertfordshire. If you need external mastic in Colney Street, it’s easy to get a quote: please call 0345 464 0079 or email us. We cover Hertfordshire from our Crawley base. Colney Street is one of 381 places in Hertfordshire we cover for external mastic. London is on our list too, about 18 miles from Colney Street.
Work in AL2 and WD7 is quoted and booked the same way as anywhere else. If you need external mastic at a property on Old Parkbury Lane, Ventura Park and Radlett Road or a nearby road, we can help. Nearby, we also carry out external mastic in Frogmore (1 mile north-west), Park Street (1 mile north-west), How Wood (1 mile north-west), Bricket Wood (2 miles west) and Chiswell Green (2 miles north-west). We also work in nearby towns such as Watford (4 miles south-west), Hemel Hempstead (6 miles north-west), Stevenage (15 miles north-east), St Albans (3 miles north), Welwyn Garden City (8 miles north-east) and Harpenden (8 miles north).
Near you in Colney Street
Locally, jobs take us to homes and businesses close to The George and Dragon Public House and Samuel Ryder Academy, among other places. The closest station to Colney Street is How Wood station, about 1 mile north-west. Nearby you will also find Kingsley Green (1 mile east) and The Maltings (2.9 miles north). The countryside around Colney Street includes Verulamium Lake and Broad Colney Lakes.
Nearby places to Colney Street
What else we do in Colney Street
Honest limits
Sealant is not the answer to every problem, and we will tell you before work begins. Sealant will not put right:
- Cracked brickwork or render that needs a builder or plasterer
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Adding movement joints to masonry that has none
If in doubt, call 0345 464 0079 or email us and we will say what we think.
What we seal
- Concrete & block
- Copings & trims
- Brickwork movement joints
- Façade panels
- Joints between brick and frames
- Render & cladding joints
Leave it or put it right?
A low-modulus sealant is chosen because it moves without pulling hard at the edges. That matters on brick, render and concrete, which can be weaker at the face. Too stiff a sealant can pull at the edges and break them. Older cottages and farmhouses around Colney Street can have timber floors and frames, and water through a failed joint can rot timber if it’s left.
Combining jobs into one visit is generally more efficient than separate visits, so it’s worth mentioning everything you’d like done. You will get one clear quote for the whole job.
Why Colney Street customers choose us
- An ARBOMaster approved applicator
- Trusted Arbo and Everbuild sealants
- Rated 4.9 stars on Google
- Sealant colour chosen to suit
DIY sealant or a professional job?
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 chosen for how the joint moves and where it is, and the work is guaranteed for a year.
Colney Street questions
Is Colney Street in your area for external mastic?
Yes, Colney Street is within the area we cover. Our work covers London and the South East. Just phone 0345 464 0079 or email us with a few details of the job.
Will you come out to Colney Street?
Yes, Colney Street is covered. We work across London and the South East, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
Can you reach joints on upper floors?
It depends on the building. We work on joints that can be reached safely. Tell us about the building and we will confirm what access is needed.
What colours does the sealant come in?
We choose a sealant colour to suit the brick, stone or render so the joint blends in. Exterior sealants come in a good range of colours.
Do I have to be there?
That depends on where the joints are. Inside work needs someone to give us access, while outside work can sometimes be arranged differently.
Do you hold any approvals?
Yes. We’re an ARBOMaster approved applicator.
Can a movement joint be filled with mortar?
No. Cement or mortar can’t stretch. Where a joint has been mortared, it can often be raked out and sealed properly.
Will the old sealant be removed?
Yes, every time. New sealant won’t bond properly to old, so the joint is cleaned back first.
Landlord and commercial work in Colney Street
Failed sealant is one of the commonest items on a check-out report, and it’s quick to put right between tenancies. We can quote for more than one property at once.
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Resealing at the right time is simple maintenance that we can handle for you.
How it works
The work is kept neat and contained to the joints we are treating. Expect the work to take anything from a few hours to several days, depending on the building, and we tell you how long to leave it before we go. For a village or hamlet like Colney Street, the journey is planned in advance: tell us about narrow lanes, gates, long drives and where we can park. We bring what the job needs, so it can be finished in one trip where possible.
- We inspect the joints and agree which need resealing and how they’ll be reached.
- The old mastic and anything lodged in the joint is removed.
- Both sides are cleaned back to sound material and primed if needed.
- Backing rod goes in next, setting the depth and keeping the sealant off the back of the joint.
- The new sealant, chosen to suit the brick or render, is applied and tooled to a neat finish.
Getting ready for the visit
- Plan for the work area to be out of bounds to pets and children
- Move anything stored near the joints
- Mention if the joints have been sealed before
Getting a quote
The more we know about the job, the more useful the quote. Tell us where the job is, what’s wrong and how much there is, and email pictures if that’s easy.