Understanding exactly what happens during an exterior cladding installation in Potton helps you know what to expect, what to ask, and how to judge whether the work is being done properly.
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Exterior cladding is not a job that looks complicated from the outside, and that can lead homeowners to accept shortcuts they would not knowingly accept if they understood what a proper installation involves. This page walks through every stage of a cladding job from the initial site visit through to the finished clean-up, so you know what good work looks like at each point.
The process below applies in principle to all cladding systems, with some variation depending on the material chosen.
Before any price is given or material ordered, the existing wall and its condition need to be assessed properly. This means looking at the substrate - what the cladding will actually be fixed to - and checking whether it is sound. On a masonry wall, that means looking for spalling, damp, or areas where the render or brickwork is loose. On a timber-framed building, it means checking that the sheathing board behind is solid and that there is no existing water ingress behind any current cladding.
The survey should also establish the exposure level of each elevation. A sheltered south-facing wall in a garden setting has very different requirements from a north or west-facing elevation that receives the full force of wind and rain. This affects both the material recommendation and the detailing of flashings, joints, and sealants.
Openings matter too. Every window, door, metre vent, and pipe penetration needs to be assessed at this stage because each one is a potential water entry point once the new cladding goes on. If the existing window reveals are not deep enough to accommodate added insulation and a new cladding layer, that needs to be resolved before installation begins, not during it.
Once the survey is done, the installer can specify the correct system. This includes:
Material quantities are calculated from measured drawings at this stage, not estimated. Over-ordering wastes money; under-ordering causes delays when the job is half done. A good installer will also identify whether any existing soffits, fascias, or bargeboards need to be dealt with before the cladding is fixed, since scaffolding is usually shared between both tasks.
Most exterior cladding jobs on two-storey or taller buildings require scaffolding. This needs to be erected before any stripping or preparation work begins. The scaffold should give safe access to the full elevation being clad, including the soffit line at the top and adequate clearance at the base to work on the bottom courses of boards.
For single-storey extensions and outbuildings, mobile tower scaffolding or a good set of hop-up steps may be sufficient, depending on the height and the duration of the work. The type of access used will be stated in the job specification and should not be changed on site without discussion.
If the building already has existing cladding, this is stripped back to expose the substrate. The condition of what is found behind often determines the next step. If the existing battens are sound and dry, they may be reused or supplemented. If they are soft, stained with mould, or showing signs of rot, they need to come out completely.
Any areas of the substrate wall that are damp, loose, or damaged are made good before the membrane goes on. This is the stage at which poor previous workmanship or undetected water ingress becomes visible. Dealing with it at this point adds to the cost of the job but is the only correct approach; covering over a damp wall with new cladding simply delays the problem and makes it worse.
The breather membrane is fixed horizontally across the face of the substrate, starting at the bottom and working up so that each course laps over the top of the one below - the same logic as roof felt. The membrane allows water vapour to escape from the wall but resists liquid water penetrating from outside.
Laps at joints need to be at least 100mm and taped at vertical joints. At openings, the membrane is cut and lapped around the reveal and taped to the window or door frame to create a continuous waterproof barrier. This detail is one of the most commonly skimped parts of a cladding installation and one of the most consequential if it is done badly.
Treated timber battens are fixed through the membrane and into the substrate at centres suited to the cladding material being installed. The battens create the ventilation gap that allows air to circulate behind the cladding, drying any moisture that does get in and preventing it from sitting against the wall surface.
The size of the ventilation gap matters. For most residential cladding systems, a 25mm to 50mm clear airspace is standard. Closing this gap by using undersized battens or over-torquing fixings so that the battens compress against the membrane is a common installation error that reduces the life of the whole system.
Counter-battens may also be fitted horizontally to create a primary drainage plane before the vertical battens go on. This is standard practice on more exposed elevations and is always the case when external wall insulation is part of the specification.
The cladding boards or panels go on from the bottom up, starting with a starter strip or foot course that sets the angle and drainage line for all subsequent courses. Getting this first course level and correctly positioned is critical; errors here compound as each course goes up.
Fixings are positioned to allow for movement in timber systems while holding the board securely. Face-fixing and secret-fixing methods both have their place depending on the board profile and the installer's preference, but whichever is used, fixing centres must follow the manufacturer's specification. At corners, purpose-made trims or mitred returns are used to close the edge of the boards neatly and prevent water entry.
Around openings, window and door reveals are clad or finished with an appropriate trim and sealed at the junction. This is the most time-consuming part of the installation relative to the area covered.
Once the boards are on, any bare timber end-grain is sealed or primed. Surface-finished boards that have been cut on site need the cut edge treated. External sealant is applied at movement joints and around penetrations. The installer should walk the whole elevation looking for any boards that have been over-fixed, any gaps at joints that are outside tolerance, and any areas where the finish has been damaged during installation.
All offcuts, packaging, old cladding materials, and fixings should leave the site before the scaffolding comes down. The area below the scaffold - including any garden, paths, or planted areas - should be left in the condition it was in before the job started. A good installer will also leave the client with any relevant care or maintenance information specific to the material fitted.
If you are planning exterior cladding on your Potton property, call Cambridge Roofers for a site survey. We will walk you through what the job involves on your specific building and give you a clear written breakdown of the work and materials before anything is agreed.
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