Painting roof valleys

[Nham]

Rusted Roof Valley

We have these roof valleys, and over the years, they developed rust on the surface due to the dirt and leaves remaining within the valleys. There were no holes in the valleys, and our friend, who is a roofing contractor, suggested painting them instead of a full replacement. Thanks to a previous post, from @EricL and @RipVanCutter, we were able to paint all the valleys. They should last another couple of years before we need to replace them. 

Materials

• Crommelin 4L Exterior Grade Brushable Waterproofer
• Bondall 500ml Ranex Rustbuster Rust Converter
• Dulux weather shield paint 
• 60 Grit Sand paper

Tools

• Heavy Duty Graden Gloves
• Latex Gloves
• Protective Eyewear
• Small Broom
• Wire Brush
• Paint Brush
• Cleaning Cloth
• Impact Drill (optional)
• Air Blower (optional)

Steps

Step 1

Cleaned Surface

Rust removal

The first step is to clean and remove all the surface rust from the valley. Preparation of the surface is critical for the waterproofing and paint to come afterwards. We used the wired brush to remove as much rust as possible. For concentrated rust areas, we used a wired disc attached to the impact. 

Tip: Wear some think garden gloves as the tile edges are sharp. 

Step 2

Rust converter will cause the affected rust surface to turn black

The next step is to inactivate the rust process. Wear gloves and eyewear when applying the rust converter solution. Using a paintbrush, apply to only the rusted area. If you get some on the bare metal, wipe it off using a damp cloth. Leave to dry for 24 to 48 hrs. The rusted area should turn black after drying. 

Step 3

Applying the waterproof paint

The next part involves brushing on the waterproofer agent using a paintbrush. We applied two coats to all the valleys. I would suggest the 2L size as we still had over 50%.

Tip: It was impossible to keep the valley clean during the application. Due to the wind dust and other matter would keep falling into the valleys. Brush off the dirt between each coat. 

Step 4

Before applicationWaterproofing stepFinal two-three coats

In the final step, we applied three coats of the exterior paint. It was more affordable to paint the valleys than to replace all five valleys we had. It took about 2-4 days, and the hardest and longest step was the surface preparation. Once that was done, the other steps were much easier to complete. 

[EricL]

Hello @Nham 

Thank you for sharing the steps you took to restoring your roof valleys. Your valley restoration looks excellent. The waterproof coating will definitely extend the service life of your roof valleys. 

Eric

[Nailbag]

Nice piece of maintenance and restoration there @Nham 

Regards, Nailbag

[webplumbr]

Thanks for sharing this information with community. Application of rust converter on only the rusted areas was quite an useful information. I was earlier under the impression that the rust converter be applied throughout the valley metal before giving it a primer coat.

[JacobZ]

Hi @webplumbr,

A warm welcome to the Bunnings Workshop community, it is wonderful to have you with us.

Allow me to tag @Nham so they are notified of your comment.

Let me know if you have any project questions you need a hand with moving forwards.

Jacob

[Nham]

Hi @webplumbr ,

For this, we wanted rust conversion so following the instructions, it was only applied to the affected areas. There is also a PDF guide for this product on the Bunnings website, which may be helpful to you.