Expansion joint sealing in Knock
Commercial sealant work in Knock for contractors, FMs and building owners: expansion and movement joint sealing in walls, decks and floors, quoted at a fixed price.
- New sealant over old, now failing
- Rain penetration at brick or block movement joints
- Joints packed with grit and debris
Need expansion joint sealing in Knock?
Send drawings, photos or a joint schedule, or tell us about the site, and we’ll come back with a fixed quote.
Expansion joint sealing in Knock, done properly
Mastic Doctor has sealed movement joints since 2005, for main contractors, FMs, managing agents and building owners. Our applicators are CSCS-carded, we are CHAS accredited and a Constructionline member, and we carry five million pounds of public liability insurance. Each job is backed by a 12-month guarantee on the workmanship. Most enquiries involve spalled or broken joint edges in floors and decks and water dripping through deck or ramp joints, across brickwork movement joints, podiums and floor movement joints and precast concrete panel joints. Searching for sealant specialists in Knock? Mastic Doctor has worked for contractors, FMs and building owners since 2005.
Travel to smaller places like Knock is planned so the work is done in one trip where possible. Send photographs, joint widths and details of the traffic first.
What our 12-month guarantee covers is the way we did the job: the preparation, the sealing and the tooling. It doesn’t extend to damage, other trades’ later work or movement the joint was never designed to take.
- Where
- Knock (HS2)
- Wider area
- Na h-Eileanan Siar
- Guarantee
- A 12-month guarantee
- Quotes
- Fixed quote, scope in writing
- Call
- 01277 525 020
- Page updated
- 3 November 2026
Owners, agents and contractors
FMs need a contractor who is easy to get on site. Tell us what site paperwork you need, such as RAMS, an insurance certificate or CSCS details, and we will confirm with the quote.
Hospitality, education, healthcare, office and retail clients book us directly too. We plan around the way the building is used, so the building keeps working while we do.
Questions about Knock
Can you work on a hospital site such as Western Isles Hospital?
Yes. We work in healthcare settings as well as offices and schools. Work is phased so departments keep running, under the site’s own rules.
Will you take on work at estates like Parkend Industrial Estate, close to Knock?
Yes. We cover Knock and the area around it, including industrial estates, business parks and retail parks such as Parkend Industrial Estate. To start, just call the office on 01277 525 020 or email a schedule or drawings with the unit, the joints involved and your access times.
Do you take on multi-site work?
Yes. Several buildings can share a single quote, with one point of contact across South East England, Greater London and Scotland.
How long before the joints can be used?
That comes down to the sealant and the temperature. Some take light use quickly, others need longer to cure, so we’ll confirm the curing time on the day.
What if there’s asbestos in the old mastic?
Asbestos is possible in some older mastics, particularly in buildings from before 2000. We check the asbestos register before cutting out old sealant in an older building, and work stops until any suspect material has been tested. Removing asbestos is a job for asbestos specialists, not us.
Do you hold CHAS accreditation?
Yes. CHAS accredited, Constructionline member, and our applicators hold CSCS cards.
Is it fine to apply new sealant on top of old?
No, never. Overlaying old sealant is a frequent cause of early failure, so everything comes out first.
More services for Knock
On site: what to expect
We schedule the visit to fit the site hours and access windows you give us. On the day, the work area is kept contained and tidy, and we check in with your contact before moving on to each new area. Travel to smaller Scottish places like Knock is planned so the job is finished in one visit where possible, so photos, sizes and a full list matter. External joints need a dry spell as well.
- The first job is to check each joint: how wide it is, how it moves and why the old seal let go.
- A fixed quote follows, naming the sealant and its movement class.
- We strip out the old seal and prepare the faces, and we tell you if any edges need repairing first.
- Closed-cell backing rod is set to depth, or bond-breaker tape in shallow joints.
- Where the maker calls for primer, it’s applied first, then the bead goes in and is tooled to a concave finish.
- We check every joint before sign-off, and the work carries our 12-month guarantee.
Getting the site ready
- Send your site hours and access windows
- Point out any areas we must not close
- Send asbestos survey details if the building is pre-2000
Getting a fixed quote
Every job follows the same four steps: send details, get a quote, we seal, guaranteed. The first step is to speak to us on 01277 525 020 or send photos by email with what you know.
Related advice
Why it’s worth doing now in Knock
Re-sealing with the same product that failed is often a false economy. If the joint is too narrow or the product wrong for the movement, it needs a different approach, and we will say so before quoting. Renewing every failing joint on one visit is the sensible approach for a place like Knock. Photos of each area help us quote the whole job.
Quantities, awkward access and phased working all shape the price. So do site requirements such as inductions and permits, along with the time of year for external work.
What you get with us
- A Constructionline member, so easy to vet
- Standard and matched colours in many product ranges
- Fixed quotes based on photographs, drawings or a visit
- Health and safety: CHAS accredited
Looking after the joints
Keep the joints in good shape with a few simple steps:
- Keep stones and debris out of open joint lines
- Treat a small split as a warning, not a cosmetic issue
- Keep product details with the building records for the next reseal
- Avoid parking heavy plant or pallets on joint lines
On car parks, winter clearance can damage deck joint sealant. Raising blades over joints where possible protects the seal and a look at the joints after winter catches any damage.
Once debris packs a failed joint, the structure has nowhere to expand. The arrises crack and break away under the load, turning a sealant job into a repair job. Keeping the seal sound avoids all of that.
Floors, slabs and movement joints in Knock
Knock lies within about 1 mile of the sea. Open joints in coastal car parks and yards let in salt-laden water as well as grit, which is why split joints are worth sealing before the edges deteriorate. Island jobs, Knock among them, are planned around the ferry and the forecast. Photos and joint sizes help us load the right products.
For an estate such as Western Isles Hospital, 4.5 miles to the west of Knock, the joints in ramps, decks and long building elevations all need attention over time.
Knock (Gaelic: An Cnoc) is in Na h-Eileanan Siar. Businesses, contractors and managing agents in Knock use us for work on movement joints. We work across 87 places in Na h-Eileanan Siar.
Work on movement joints is covered throughout HS2. If your site is on Seaview and A' Chnuic or close by, we can quote for movement joints. Main routes into Knock include the A866. Close to Knock, our area also takes in Na h-Eileanan an Iar (1 mile west), Aiginis (1 mile west), Lower Bayble (1 mile east), Garrabost (2 miles north-east) and Pabail Uarach (2 miles east). For island and remote sites, we plan travel and materials carefully, so the full address helps from the start.
What’s near Knock
A little further out are Western Isles Hospital (4.5 miles west).
When it isn’t the sealant
Part of a good diagnosis is knowing where sealant stops. You’ll hear from us if the cause turns out to be one of these:
- Leaks coming from the membrane rather than the joint seal
- A joint that has to be widened or re-detailed before it can work
- Proprietary pre-formed expansion joint systems
Not sure which it is? You can ring 01277 525 020 or send details through our quote form and we’ll tell you honestly.
What we seal
- Brickwork movement joints
- Precast concrete panel joints
- Blockwork control joints
- Cladding panel joints
- Podiums and floor movement joints
- Car park decks and ramps
Signs you need expansion joint sealing in Knock
When the movement exceeds the sealant’s capability, the bead tears. A joint that’s too narrow for the movement, or a product with the wrong movement class, will split through the middle. Resealing like for like often fails the same way, so we check width and movement before quoting.
Site and facilities staff are often the first to spot these:
- Chipped joint edges on forklift routes
- Previous reseals laid over old sealant
- Movement joints with split or torn sealant
- Rain penetration at brick or block movement joints
For an occupier at a site such as Parkend Industrial Estate, 3 miles to the west of Knock, the joints at loading doors and dock levellers usually see the hardest wear.
Comparing quotes
- How they’ll work around occupants
- Whether old or failed sealant will be cut out, not overlaid
- How joint depth will be controlled
- What site paperwork they can supply