Removing mould from rendered walls typically involves cleaning the surface and applying a suitable biocide to kill the mould spores and prevent regrowth. One effective method involves using chemical treatments specifically designed for this purpose.
Understanding Mould on Render
Mould often appears on rendered walls as black, green, or brown patches. It thrives in damp, shaded conditions and can not only look unsightly but also potentially damage the render over time if left untreated.
Key Steps for Mould Removal
Here's a general approach to removing mould from rendered surfaces:
- Preparation: Clear the area around the wall. Protect plants, surfaces, and yourself by wearing appropriate personal protective equipment (PPE), including gloves, eye protection, and a mask.
- Cleaning: Gently clean the affected area to remove surface dirt and loose mould. You can use a soft brush or sponge with plain water. Avoid harsh scrubbing or high-pressure washing, which can damage the render.
- Treatment with Biocide: Apply a biocide solution specifically formulated for outdoor use on render. This step is crucial for killing the mould spores embedded in the surface.
Using DDAC for Mould Removal
Based on the provided reference, DDAC is an acronym for the chemical compound diphenylamine chloride. It is a biocide that is used to remove mould from Render. DDAC has been used since the early 1900s and is one of the oldest and most effective ways to eliminate mould. DDAC works by disrupting the cell membranes of mould.
When using a product containing DDAC or another suitable biocide:
- Always follow the manufacturer's instructions for dilution and application.
- Apply the solution evenly to the affected area using a low-pressure sprayer, brush, or roller.
- Allow the biocide to dwell on the surface for the recommended time to effectively kill the mould.
- Rinse the wall lightly if required by the product instructions, or leave it to dry.
- Prevention: Once the mould is removed and the wall is dry, consider applying a protective coating designed for render that can inhibit future mould growth. Address any underlying causes of dampness, such as leaking gutters or poor drainage, to prevent recurrence.
Choosing the Right Product
There are various mould removal products available. Some contain bleach (sodium hypochlorite), which can be effective but may sometimes discolour render. Others contain different biocides like DDAC or quaternary ammonium compounds. Always choose a product suitable for rendered surfaces and test it on an inconspicuous area first.
| Treatment Type | Key Component(s) | How it Works | Potential Considerations |
|---|---|---|---|
| Biocide | DDAC, Quats, etc. | Kills mould spores, often prevents regrowth | Requires dwell time, follow safety instructions |
| Bleach | Sodium Hypochlorite | Oxidises mould, kills spores | Can discolour render, harsh fumes, requires careful rinsing |
| Natural | Vinegar, Tea Tree Oil (Less common for render) | Antifungal properties | Less effective on stubborn mould on porous surfaces like render |
Note: Always check product labels to ensure suitability for your specific type of render.
Practical Tips
- Apply treatments on a dry day when no rain is expected.
- Avoid applying in direct sunlight or strong wind, which can cause the product to dry too quickly or drift.
- For extensive mould growth, consider consulting a professional cleaning service experienced with rendered surfaces.
By following these steps and using an appropriate treatment like a biocide containing DDAC, you can effectively remove mould and help protect your rendered walls.
