Lots of customers ask me about filling gaps. If you have wide gaps in your floor, gap filling could be the answer. It's an effective way of plugging the gaps so air and dust cannot rise through them and into the room. When the boards were originally laid they would have been fairly tight. The natural shrinking of the wood means that gaps can be as much as 6mm wide. On the ground floor or if you have a cellar there will be a constant draught coming from the gaps.
There are two methods for filling gaps one is to use a filler but it cracks and falls through after a while especially if the gaps are more than 3mm wide. The second method the one I use is to fill them with strips of wood. The strips are cut to the thickness of the floorboards, I then put some wood glue into the gap and with a large mallet hammer the strips in to create a tight seal. The sanding machine then sands them down to the level of the floor.
Lots of my customers say how warmer the room is since the gaps have been filled, some have even said they have noticed a big difference in their heating bills. If the rooms are on the 1st floor gap filling isn't necessary as there is no air passing under a 1st floor room, so its more of a cosmetic exercise.
Floors that have had the gaps filled look great, the floor has a continual look to it because there are no breaks in the surface, the gaps tone in with the floorboards really well as they are brown much like most pine boards.

Due to the movement in floors the filler paste method can be unreliable and drop through or get sucked up in the Hoover with gaps over 3mm wide.

FINISHED FLOOR