Rubio makes a product that give wood floors that grey look. Check them out online.

Filling gaps between timber floor boards can lead to disaster and is best avoided. Sanded and polished timber floors tend to swell slightly during the humid months of the year and shrink again in the drier months. This creates movement in the timber floor. If you fill the floor when the gaps are at their widest and then encounter some humid weather, the floors will swell, closing the gap and forcing the filling out of the grooves and cracking the timber floor finish. This looks far worse than gaps in the polished timber floors. If you can't live with the gaps, laying a engineered timber floor over the top may be your best choice. Painting your floors white is also best to avoid as this only accentuates the size of the gaps. Good luck with your decision. Engineered timber floors

Hi Julie Tiles would be more durable with dogs however floor boards will be warmer and cosier especially in the bedrooms. I have floor boards and house dogs and have no problems though the boards are lighter in colour so don't show scratches readily. Plus any scuffs add to the appeal of floor boards. You will need to check with the supplier if you decide on boards as to whether they can be direct stick or have to be floated. This will be influenced by the quality of your slab and the natural moisture content of the soil. If you have to float them it will sound a little hollow even with the acoustic underlay. I would personally go for floor boards over tiles but qualifying this by saying I always prefer them over tiles in most situations. Hope this helps

Thanks to nickybaruch I am now considering doing the floor (which is now sanded back ready for finishing off) with white liming with a slight tint colour in it. Some say you have to be very careful when liming. Is this a problem? I would have thought it would be just like putting on a stain? Anyway doing it that way we would still see the grain of the timber floor which would be lighter than the dark cedar it was before and keeping the pine lined ceiling with the cedar coloured beams will blend in well I think with the lighter timber floor and the white walls we now have. What do you think?