How to waterproof a fibreglass roof?

[Kokonut]

Waterproofing a Houseboat Fibreglass Roof.

Bastion 15kg Exterior UV Stable Membrane, I presume this is a Bunnings brand product?

Just wanted to know, if the above product can be applied to fibreglass, specifically, the external fibreglass roof of a houseboat (currently has weathered paint on it). There will be no walking traffic on it. It will eventually be covered by decking timber panels, which will sit or float above the roof by about 50mm, and there will be limited sun. Rain will drip through the gaps along the timber floor panels. Many thanks.

[JacobZ]

Hi @Kokonut,

Thank you for your question about waterproofing a fibreglass roof on a houseboat.

I'm not 100% certain about that one. 

I believe it should be fine as waterproof membranes are often applied over fibreglass pools, but please allow me to get in touch with the manufacturer when they open on Monday to confirm this products compatibility for your specific application. 

In the meantime, if you have any questions, please don't hesitate to ask.

Jacob

[JacobZ · Accepted solution]

Hi @Kokonut,

I've contacted Bastion's technical team who've advised me that there are no issues with using the Bastion 4L Exterior Waterproof Membrane on a fibreglass houseboat. 

You should ensure the surface is well cleaned to remove any dirt, dust or contaminants such as salt before applying Bastion 5L Waterbased Primer. 

Once the primer has dried, immediately apply the waterproofing membrane to avoid any salt or contaminants getting onto the primed surface.

Ensure you follow the manufacturer's instructions for best results and wear all relevant personal protective equipment including a mask and gloves when applying the primer and membrane.

Let me know if you have any further questions.

Jacob

[Kokonut]

Much appreciated Jacob, thank you for the thorough explanation and the additional info on the priming, which I overlooked. Looks like I just need to wait for a warm day in this miserable cold Sydney season to make a start on the project.