Modern waterproofing of aged slate roofs without full stripping
Over time, aged fibre-cement slate roofs can develop cracks, breakages and fixing faults. The slate surface may become porous, joints and overlaps can lose their watertightness, and extreme weather can further accelerate the deterioration of the covering.
Leaks often first appear in just one room or after heavy downpours, while smaller, barely visible defects may have formed at several points on the covering. In such cases, repairing individual slate tiles no longer provides a long-term solution in every instance.
The technology we use makes it possible, in many cases, to refurbish suitably conditioned, fibre-cement slate covered roofs without full stripping. We create a continuous, modified bitumen waterproofing over the existing covering, forming a uniform protective layer across the entire roof surface.
Refurbishment without stripping is faster, can be more economical, and involves significantly less waste. We decide on its suitability in every case based on an on-site survey of the roof’s condition and load-bearing capacity.
The slate roof refurbishment workflow
Detailed condition survey
We examine the condition of the slate covering, fixings, substrate structure, eaves line, ridge, chimneys and other roof penetrations. We verify whether the existing covering is suitable for receiving the new waterproofing system.
Identification of the covering material is particularly important. Any asbestos-containing elements can only be dismantled, replaced and handled in compliance with the relevant occupational safety and waste management regulations.
Repair of damaged and loose elements
We professionally secure loose, displaced slate tiles, and repair or replace damaged sections as necessary. We restore unstable surfaces to provide a properly firm substrate for the new waterproofing.
Preparation of the slate surface
We carefully clean the roof surface using a procedure suited to the material and its condition. We remove adhesion-inhibiting contaminants and loose parts, while ensuring we do not unnecessarily load or damage the existing covering.
Precise surface preparation is one of the most important prerequisites for the durability of the entire waterproofing system.
Reinforcement of the eaves connection
At the lower edge of the roof we form a stable connection surface from properly fixed galvanised steel sheet or other sheet-metal flashing matching the system. The lower edge of the new waterproofing membrane connects to this, so that precipitation can be safely directed into the eaves gutter.
Bitumen priming
We apply a bitumen primer to the cleaned and repaired slate surface. The primer binds surface dust and creates a suitable adhesive bridge between the existing covering and the new bitumen waterproofing.
Vapour control and ventilation solution
During refurbishment we check the roof structure’s ventilation and vapour control performance. Where necessary, we install vapour vents to promote the escape of any moisture present in the structure.
The number and placement of vapour vents is determined in every case based on the roof’s size, design and existing layer build-up.
Preparation of roof penetrations and junctions
We separately reinforce the surroundings of chimneys, roof windows, antenna mounts, vents, ridges and other junctions. Where necessary, we also repair or supplement the flashing structures.
At these junctions we can apply multi-layer waterproofing to create durable protection even on the most heavily used parts of the roof.
Creating the continuous waterproofing layer
We install a high tensile-strength, polyester-fleece reinforced, modified bitumen waterproofing membrane on the roof surface. The membranes are fixed by torch bonding, and the overlaps are welded across their entire surface.
The waterproofing thus created forms a uniform protective layer above the individual slate tiles. The mineral-granule finished upper surface protects the membrane from UV radiation and the damaging effects of the weather.
Final inspection
On the completed roof we check the membrane joints, junctions, perimeters and all roof penetrations. The work is only handed over after a full inspection of the entire waterproofing system.
Advantages of slate roof refurbishment without stripping
- In many cases the costly stripping of the entire slate covering can be avoided.
- The construction duration can be significantly reduced.
- Less demolition waste is generated.
- A continuous waterproofing layer is created above the individual slate tiles.
- We separately reinforce the problematic junctions and roof penetrations.
- We provide a written workmanship warranty of up to 10 years for refurbishment carried out with the appropriate technical content.
When refurbishing a slate roof, selecting the right technology is particularly important. Therefore, every project of ours is preceded by a detailed condition survey and customised technical design.
Request an on-site survey and a detailed, itemised quote!
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