Floorboards finishing a different colour

Hi guys,

I'm having some challenges working out why my floorboards are turning out the way they are. Basically I've hired a floor sander, sanded down my timber floors and then applied Cabot's CPF Flooring (water-based polyurethane).

The challenges I'm having is around differences in colour after applying polyurethane. I've attached a photo which shows an example - you can see the left hand side there's a strip that's noticeably lighter. Now I think I know what caused this, but I can't seem to figure out (googling doesn't yield results) how to correct it. Basically the areas that show up as lighter is the areas that I have passed over with the floor sander twice (once to go from left to right but then I went over a small area from right to left to get closer to the wall on the left). Does anyone know how I can correct this?

The other challenges I've had is that there are some areas where I didn't pass the sander over twice.. but it's still showing a distinctively lighter colour in flooring. Similar issue to above, I'm just not sure what caused it or how to fix it.

Has anyone experienced this? The closest I can see when googling is if someone dropped their drum sander or held it over an area for a long period but I did neither that (the sander moves as soon as its started).

Thanks

 

It's clear, no tint. It's this product: Cabot's CFP Floor Water Based

Also realised I forgot to add the image so have added it below:

 

That section on the l/hand side was that the only section that was sanded, or the entire floor as you would have to sand that section to blend into the original colour..
Mabye when you prepare the Polyurethane ,mix it for a few more minutes till it's like water.

 

Did the boards look a different colour before you added the poly?

Try asking on the Renovate Forum too as there are some very experienced DIYers there.

 

I'll admit, I can't really understand the first part of your response . The whole floor was sanded, just that section on the left received more passes of the sander.

The boards before I sanded looked the same. After I sanded, the mark on the left was there not applying polyurethane made it a lot more obvious. There are other areas of floorboards where I might’ve sanded deeper and they're also looking similar just in longer rows.

Good idea on the Renovate forum. I'll try there as well but I think I need to wait for an admin to approve my post.

 

Sorry to say this and I guess this is what you don't want to hear but ... if it were me, I'd be thinking I'd have to resand the whole lot again to get it even. Maybe twice. It's amazing how that extra sanding shows up so clearly. Must need long continuous movement, with no heavy pressure anywhere. I can see that section over near the power point too.
Sorry. The joys of diy.
Plus, I'd be going the full oil poly for best coverage and durability.

 

OK - if the marks were only there after you sanded - but before the poly -then the issue isn’t the poly it’s the sanding.

I suspect you didn’t sand enough to get all the old varnish off over the entire floor. And the darker parts still have some of the old varnish/stain on them.