Wavy Floorboards - can I sand them down flat?

[goldenshoes]

My new to me house has solid oak flooring that has been stained and varnished to dark brown and I'd love to sand this down and go back to the natural colour. I did a test patch and it looks to be nice and light.

However, the floorboards are all very wavy and I wonder if even an industrial sander will take this down?

Googling isn't helping much as most information I can find is about 'cupping' and this doesn't seem to be that, more a wave through the width of the board rather than just at the edge joins. I looked at the schedule for the house from the last sale before me 7 years ago and the waves are apparent in those photos so it's been like this a while, and is possibly part of the style?

Any words of wisdom from mumsnetters before I embark on a weekend of sanding hell?

So they’ve been hand scraped to give a rustic look. That might help when you’re googling.
Do they look any better now you know they are meant to look that way?

start by checking for damp, especially under the floor. Look at your airbricks and verify they are clear, and there are no signs of damp at the bottom of walls, especially in the kitchen or other downstairs rooms containg water pipes.

The rings in a tree cause planks cut from it to "cup" across the width, if humidity increases, which may be what you are seeing.

If humidity decreases, they curve the other way

(planks can be cut in a way to minimise this, but it is wasteful of material, so expensive).

I found this utube, which has a good diagram at the start.

I don't know how to solve it.

if you do flatten them, and then humidity changes, they may warp the other way.

Isn’t it just that the OP doesn’t like the style of them, rather than there being anything wrong with them? I think they think they’re meant to be flat.

Don't try to sand them. Look at the edges - you might have to pull the skirting board off. There should be a gap all the way round. If the edge of the boards is tight to the wall anywhere, changes in humidity will make the boards expand and curve as you describe.
The carpenter who did my floor didn't believe how much boards can swell. I found a clever tool in Screwfix for him to buy so he could trim all the edges. The boards flattened slowly over two weeks. They were new, old boards might respond differently.

This is hand scraped not damp or a fault.

I have this. My instructions say it can be lightly sanded to rectify damage but I wouldn't use a sander as that's designed for flat surface.

Oh I see... Why would you do that to floorboards? That would be sanding hell.

Oh I see what you mean. Not cupping.

Thanks for the replies.

@SheWoreYellowIt's the dark colour that I don't like rather than the waves but in order to get rid of the varnish I'll need to sand the waves down which will be difficult and time consuming! I'd like to avoid going to the trouble of hiring a sander etc if they can't be sanded down or will need something even more heavy duty

@PigletJohn The house is damp so that could have caused it. However, the waves are fairly consistent and the fitting looks good with no obvious cupping or gaps so I think it's probably the style.

We're looking into better venting for the house (old cottage) when we come to renovate in the next year-ish, and in the meantime running a dehumidifier. If we sand them now we can see if it's worth lifting and saving them during our renovation to re-lay once the building work is done but if I can't get rid of the colour then I'd rather just replace them with something lighter.

@SeanChailleach

Oh I see... Why would you do that to floorboards? That would be sanding hell.

Oh, more replies, thank you!

@SeanChailleach nooo! That's not what I wanted to hear! But yes, good to know before starting!

@GoldenBlue of that's interesting. I wonder if there's a specific type of sander I could use, I shall look into that, thank you

@SheWoreYellow

So they’ve been hand scraped to give a rustic look. That might help when you’re googling. Do they look any better now you know they are meant to look that way?

This is very helpful for googling thank you!

Oh I didn’t have to google, I know because we have them! We paid extra for them to be like that

Me too 😊 they look lovely and more age appropriate for our house

Had wavy boards similar to yours.

They were fitted to a house I owned about 11 years ago, by Machells of Leeds.

At the time they were fashionable and very expensive.

I dont think you would have been able to sand them, over and above taking off the top varnish layer, because of the way they were structured. They were, albeit very thick, laminated boards.

Am attaching the supplier details. Maybe they could advise you.