I recently did a job where leaking window frames had rotted out a large section of the living room’s floor. The disrepair had been allowed to go on for quite some time to where not only was the flooring rotten, but the timber beams and joists as well. The leak was sealed up and I began the task of redoing the entire floor which included replacing several large beams and many smaller joists.
Flooring is sometimes installed before the walls are completed, but it should never be nailed or otherwise fastened past the outer boundary of where the walls will eventually be. In other words, flooring should always be installed so it can be redone without having to be manually cut where it disappears into the wall. Nailing down the edges of flooring ends that are sunk deeply into the walls makes taking up old flooring a nightmare!
When done properly, flooring can be pulled right out from under the walls after trimming, nails, and glue are no longer an issue. Being that floors often endure large and repetitive loads, using wood glue in addition to flooring nails or staples is recommended. When taking old flooring up, first remove the trimming, then, by using a crow-bar and the closest joist for leverage, break the glue seal and dislodge the nail from the flooring simultaneously.
It’s often necessary to make a starting cut with a circular saw to create a gap from which you can begin prying with the crow-bar. You should always start from the tongue side of the flooring. If you’re lucky you’ll make the cut on the right side on the first shot, but if not, just switch to the other side. There’s no way to tell from the top, unless the flooring is rotten and you’re able to start there, so you’ll just have to pick a side.
This makes your job much easier as the flooring can be “popped” free from the nails with the crow-bar, and will then cleanly come loose from the adjoining flooring. Doing this the other way around – as in, starting from the groove side – is frustrating, as the tongue side is still nailed and must be pried loose.
Keeping the old flooring in tact as much as possible is important if you want to keep your cleanup simple. As tempting as it is to go berserk on the old flooring and tear it all up violently, it pays to think about the time it will take to clean all that up. By keeping the old flooring in tact, you can bundle them all up and dispose of them quickly and efficiently.
However, there are times when the flooring is so rotten that it breaks up into small pieces as you pry it up. At times like this, don’t worry. Just use a large dustpan and broom and sweep/scrape up the fragments into strong canvas bags. Normal plastic bags will almost certainly tear with the sharp edges and nails that come with this type of debris.
Once I removed all the old flooring and the rotten beams and joists, I proceeded to remove all the nails that were still sticking up from the remaining good joists. Remember here that the old flooring was simply ripped up from the joists leaving all the nails as they were. Residual glue and flooring fragments that remained on the joists had to also be removed to a reasonable degree for the new flooring to sit well.
I was now ready to lay the new beams and joists. This particular room had a concrete floor with bolt anchors sticking up to hold the beams down. By slipping wood slivers underneath the beams, you can control the vertical spacing from the concrete floor as well as the level, while a nut can be tightened down on the bolt to hold the beam securely down. You should of course, still nail or screw the beam to the slivers. (See photo above)
The joists can now be fastened perpendicularly over the beams. I used 30 centimeter spacing between joists, center to center. Note that the perimeter where the flooring ends should be “boxed in” with joists, as those ends will not be supported on that one side and will therefore need support between joists as well. In other words, the entire perimeter of where the flooring is to be installed should have full, unbroken joist-support.
Once the new beams and joists were fastened in place, I could begin laying the new flooring. In this particular case, the client wanted to lay the new flooring starting partway, as only about half the room actually needed to be changed due to the rot. (However, because it is almost impossible to find the exact same color and pattern that matches the existing flooring, it is recommended to redo everything.)
But if looks aren’t much of an issue, this is certainly a cheaper and easier course of action. It turned out that the joint between the old and new flooring would need to both be groove ends, which meant that the strength of the tongue and groove joint could not be utilized. This joint would now have to be treated as a “perimeter” as mentioned above, and be reinforced underneath along the entire length of the joint.
From here I glue and staple (blind-nail) the new flooring on systematically, using an air compressor and 38 millimeter staples (see What is Blind-nailing?). After completing the first row of flooring, I placed several new packs of flooring on top of the joint overnight to ensure the joint was flush and level. This is because the edge of flooring that meets the old flooring directly won’t be nailed as there would be no way to do so without them being seen from above.
But then you would need to ensure you use sufficient glue as it would essentially be the only thing holding it down. Use any flat, heavy object to bear down on the key points to ensure good joints. After the first row is done, I continued on to the second one. Flooring here in Japan often comes in roughly 182 by 30 centimeters, and can be staggered in three repeating patterns.
More specifically, if the first row starts off with a full sheet, the second row starts with two-thirds that, and the third row starts with one-third. Remember though, to start from the same side of the room. The joists should be spaced out so as to support each flooring joint wherever they may be. In this way, the flooring joints are staggered and adds to the integrity of the joints as well as the overall aesthetics of the floor.
And of course, the flooring should be tucked at least past the point of where the outside of the trimming would be, preferably several centimeters past to be safe. It’s never a good idea to cut the flooring off too close to the edge of the wall unless you’re absolutely sure the trimming will cover it in any and all circumstances – such as temperature and humidity related shrinkage.
The final pieces can be nailed close to the edge so as to be covered by the trimming. In my case though, the flooring finished with the veranda, which was unfortunate, as any nail heads could not be concealed by trimming. I had to use the glue and weight technique, which isn’t something I would want to use too often due to its adhesive inferiority to using both nails and glue.
The reason I decided to start at the joint with the old flooring (opposite from the veranda) was because I felt it was more important that that particular joint was more or less perfect due to it being in the center of the room and the fact that the difference in pattern and color would draw attention. After all the flooring was laid, I finished by nailing the trimming on.