How to fix gaps in corners of weatherboard house?

Question

Hi there!

I have an issue - we've installed Linea (Hardie) weatherboard - and have used their corner pieces for the corners - but they look absolutely awful - I can see gaps - and can't get in there with gap filler (especially at the bottom of the gap where the gap is the most narrow).

I really don't understand why the Hardie Linea Weatherboard installed with the Hardie corners looks so bad!

How should it be?

I think I recall seeing that sealant wouldnt be needed or shouldnt be used (to allow water out) at these joins - but when painted white - and the gaps being 'black space', they're so visible!

If you think the weatherboard should have been cut a bit longer, it can't have been - as it has to slot in behind the lip of the corner piece, The corner piece also must be installed first. When I look at other homes it always seems as though the corner is something that goes on last. ???

This will be an outdoor seating area so will be right in view! :-(

Please help - or describe what we should have done.

The first 2 pics are where I've used the proper flexible sealant and painted (sikaflex something). The can see I cant get the nozzle or my finger right to the bottom).

The last 2 pics are where I've left it un filled and there's a gap.

JacobZ · Answer

Hi @lisyloo725,

I've just spoken to James Hardie's technical team who have advised that there is no issue with sealing the ends of the weatherboard that sit inside the boxed corners. It's not advised sealing the bottom edge of the weatherboard, as that can help water drain, but the ends are perfectly fine to be sealed.

You've honestly done a neat job sealing them in those first couple of photos, but if you can get the sealant a bit lower, it would certainly look more finished. I'd try using a fresh, uncut caulking tip, and starting at the bottom of the gap. If you are still unable to get the sealant in there, you might have some more success using a flat applicator tool such as this

https://www.bunnings.com.au/uni-pro-25mm-real-good-paint-scraper-25mm_p1674074

.

After your sealant has cured, you can paint the ends and the inside of the boxed corner to give it a more finished look.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob

Nailbag · Answer

Hi @lisyloo725

Though as you noted, non-timber weatherboards don't require all end cuts to be sealed with a primer. I still by habit do so to seal the dusted ends. For me I find I end up with a smoother seamless join once primed over, sanding and painted.

The ends to the corner stops must be finished with a flexible exterior silicon for waterproofing. As well as along the under side of each weatherboard where it meets with the one below.

From your photos, the undersides have no silicone. You can achieve a neater end if you take a little more time in your measurements to get the board finishing just a couple of mm from the end stop. Then it will only require a thin bead of silicone for a much neater finish.

If using a water-based silicone, spray a light mist of water over the silicone and remove the excess with something like one of these silicone scraping sets.

I have a lot of rotted sections of timber weatherboards in the reno house we recently moved into. And this is essentially the process I follow as I work through replacing them.

Nailbag

JacobZ · Answer

Hi @lisyloo725,

I'm not 100% sure what the best approach in this situation would be, so I'd like to reach out to James Hardie for some advice.

Please bear with me, I will get in touch with them tomorrow morning when they reopen.

In the meantime, allow me to tag @Nailbag to see if he has any experience with this system and might know the solution.

Jacob