How to fill gaps between James Hardie Linea weatherboards?

[ironbark]

Hi, 

I have a large shed with is out of the weather and has J.Hardie Linea weatherboards, which look great. There are some gaps between some of the boards and I’ve been using the recommended polyurethane sealant. I’m really struggling with the fumes, even though I’m outside. I really don’t want to use this product anymore, it’s making me feel pretty awful. 
 I need to take another approach, is there another filler I can use that doesn’t emit these fumes? Possibly some filler mixture like Agnews multipurpose filler,Selleys Spakfilla or similar. 
Any suggestions would be greatly appreciated. Thank you 😊🔨🪚🪛

[EricL]

Hi @ironbark 

How long and big are the gaps? I take it that there is movement occurring between the weather boards. If that is the case, you'll need a sealer that is flexible. If you continue to use the polyurethane sealant, I propose wearing a Citeco Half Face Respirator A1P2 Kit. This mask is designed to protect you from organic vapours such as solvents, Paints & Thinners. This includes vapours coming from polyurethane sealants.

Another product you can try is the Selleys 290ml Clear Storm Waterproof Gutter And Roof Sealant. It delivers a waterproof seal on almost any material and can even be applied in the rain to stop leaks immediately. It’s ideal for sealing skylights, gutters, downpipes and windows, and can be painted over with water-based paint. It’s not suitable for permanent water immersion or plugging leaks subject to pressure. 

Unfortunately, multipurpose fillers are not flexible and will therefore not work well with weatherboards.

If you need further assistance, please let us know.

Eric