Dealing with untreated sunburnt timber

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Benoire

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#302866 29-Dec-2022 22:54

Hey folks,

I've been slowly building a wood cabin for a wfh office. I'm now at the point of laying the floor but due to delays in building the cabin due to covid and other reasons, the floor boards have suffered from sun burn due to being exposed whilst we where sick and out of action.

See this image of them laid out in the cabin.. the timber is nordic spruce so light coloured with the burnt bits the darker orange colour.

What I'm seeking is advice on how to treat this. The plan was to poly the floor but clearly I need to deal with the colour differences. Can you stain/dye the floor first to cover the differences or does it really need to be sanded? Can this actually be fixed?

Happy to get any advice and thoughts from any resident wood expert!

Thanks,

Chris

Bung

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#3015211 30-Dec-2022 04:25

Awake rather than expert. Currently sanding a newly laid pine deck to clean it up and even out colour differences in timber bought at different times. 80 grit seems coarse enough for fast results. Resene have a page on colour change of timber floors. That suggests using a timber bleach (not chlorine) will make it more susceptible to UV change in future. UV will always be an issue and furniture/rug placement will show. The type of finish can help.

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BlueOwl

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#3015226 30-Dec-2022 09:17

Sanding.

Or if you know someone with a thicknesser they could skim 0.5mm off the surface.

With stains you'll never get an even colour texture across new pine, unless you sand then use pre-stain conditioners. - it will likely look worse if you apply stain as they are. Alternatively, paint.

Benoire

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#3015232 30-Dec-2022 09:26

BlueOwl:

Sanding.

Or if you know someone with a thicknesser they could skim 0.5mm off the surface.

With stains you'll never get an even colour texture across new pine, unless you sand then use pre-stain conditioners. - it will likely look worse if you apply stain as they are. Alternatively, paint.

Cool thanks. I've likely got spare boards so will try sanding some of those down first. I can hire a floor sander if necessary, as using my random orbital would take quite some time and this cabin has gone on long enough! I just wanted to get the floor to a decent state before staining/poly but if it wasn't possible now then I'd probably cover with rubber interlocking matts or something.

Ge0rge

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#3015233 30-Dec-2022 09:39

Couldn't just lay them out as random as possible, and call it a feature?

Benoire

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#3015235 30-Dec-2022 09:48

Ge0rge: Couldn't just lay them out as random as possible, and call it a feature?

If it was a random pattern on the boards then I could.. in this case, the damage is neatly forming square and rectangular strips from where the boards where laying on top of each other /sigh.

eracode

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#3015238 30-Dec-2022 09:51

If you’re going to try sanding, could I suggest that you could do the boards individually before installing - use a power sander (rather than laboriously by hand) and use a belt sander. An orbital sander will be scuffing across grain half the time and will not give a good finish. A belt sander sands with the grain and will look much better.

Alternatively use a power planer - quicker and easy to take 1mm off the surface. If you have trouble controlling the planer and get small ridges in the surface, plane first then finish with a light belt sanding.

Sometimes I just sit and think. Other times I just sit.

Ge0rge

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#3015239 30-Dec-2022 09:54

Where abouts are you? I have a thicknesser.

tweake

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#3015246 30-Dec-2022 10:33

first thing is can you flip the boards over? sun stain should only be on one side.

the other thought is oxalic acid which may just bleach the stain out.

Jase2985

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#3015277 30-Dec-2022 11:46

tweake:

first thing is can you flip the boards over? sun stain should only be on one side.

that was my first thought, flip them over unless they are not dressed on that side or something?

Bung

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#3015289 30-Dec-2022 12:27

A lot of flooring isn't symmetrical. The back could have a relief cut.

It is a floor not a table top. The end result will only be seen in closeup by ants and spiders 😀

Benoire

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#3015290 30-Dec-2022 12:33

The back has a bevelled edge which looks quite silly when I tried it before I laid ~1.4m in to the cabin! Ultimately I'm just trying to reduce the darkening on the boards exposed to the sunlight too much to not make a stain & poly look worse.

eracode

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#3015686 1-Jan-2023 10:03

Ge0rge: Where abouts are you? I have a thicknesser.

Now you’re talking! Thicknesser FTW - but OP didn’t seem to respond.

Sometimes I just sit and think. Other times I just sit.

Ge0rge

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#3015687 1-Jan-2023 10:08

eracode:
Ge0rge: Where abouts are you? I have a thicknesser.

Now you’re talking! Thicknesser FTW - but OP didn’t seem to respond.

Haha thanks! it's a fantastic tool and makes jobs that need it soo much quicker and easier! I need to get a decent jointer to go with it, but being on single phase makes it more difficult.

More on topic, it happens often here I notice that the OP will ask, and then not come back.

Benoire

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#3015692 1-Jan-2023 10:31

Howdy people, still here.. just busy with end of 2022, kids and finishing putting the floor down. I appreciate the advice and as the floor was going down already, I'm going to use the flat sander and remove some of the sharp edges from the sun damage where it's clear boards were lying on top of each other... Now the floor is mostly down the actual damage looks quite nice as a colour variation so will poly it once sanded and see how it goes.

@Ge0rge, thanks for the offer of the thicknesser... had I not started laying the floor I would have seen if we could have taken you up on the offer.