FLOOR REPLACEMENT

By Dave Casper

 

The floors of many of the Hydrostreams I’ve seen have been rotted in areas mainly because of improper methods of attaching items such as gas tanks, trim pumps, rear seats, battery hold downs etc. The floor of my Vegas was weak in these areas as well as some others so I decided to replace it. For those that are unsure of the condition of their floor there are a couple of ways to check it. First, if your hardware is mounted with wood screws directly into the wood, remove the screws and check the condition of the wood around the holes. If the wood is still solid, now would be a good time to install wood inserts as discussed in Mark Casper’s article. If the wood is rotting, you will have to find out how far the damage has spread. This can be done by either using a moisture meter to measure the moisture content in the wood, by probing the floor surface with a tool such as an awl to check for sponginess, or to simply keep removing rotted wood until it’s gone. Other areas of the floor can be generally checked simply by walking on it and checking for a soft or spongy feeling. A plastic mallet can also be used to more thoroughly determine the floor’s condition. By tapping the mallet all around the floor, you should get a solid feel and sound if the floor is in good condition. If you don’t, further investigation is necessary.

 

The first step is to remove the area of the floor that will be replaced. In my case, I removed all of the floor from the transom up to the front seat mounts including the driver’s seat area. The most critical thing to do is to find out exactly how thick your floor is. It should be ". There should be an opening in the floor by the drain plug where the thickness can be measured. To start cutting the floor out, you MUST use a saw that has a means to limit the depth of the cut. The first 5" or so of the sides of the floor lay directly on the hull so if you cut tooFloor1~1.jpg (100295 bytes) deep………..bad things will happen! At the back of the floor just in front of the transom, the floor also attaches directly to the hull where the hull curves upward from the drain plug – pad area to the transom. Also, there are two stringers approximately 6" apart running front to back above the pad area. Mine also had two areas of a thin fiberglass layer laid between the stringers – probably not important if cut through because the floor will connect them. The critical areas to be very careful cutting near can been seen in the picture to the right. Begin by removing the carpet from the area of the floor to be replaced. If the carpet is going to be reused, use a razor knife and cut carefully so that the carpet can be replaced with the smallest seam possible. Next, draw lines on the floor to guide you while cutting the floor out. To make installing the new floor easier, make sure your lines and cuts are straight and square to each other. If the entire width of the floor is to be removed, try to determine where the edge of the plywood ends. In the case of my Vegas, it was easy – it butted up to within about " of where the hull curves upward from the floor. Next, use a saw with the depth of cut set to the thickness of the floor and start cutting it out. Again, be VERY CAREFULL that you don’t cut into the hull. A couple of notes:

 

  1. Cutting out the floor in sections makes it easier.

  2. The sections of the floor over the edges and the stringers will probably still be glued down and difficult to remove. These areas can be removed by carefully using a wood chisel to remove the plywood one ply at a time – not the fastest job in the world!

 

My floor required replacing the area under the driver’s seat but the seat pedestal was still in good condition. I used a Sawzall and cut the pedestal off where it joined at the floor so it could be fiberglassed back on later. If enough of the floor has been removed to do it, now is obviously the time to inspect the hull from the inside and make any needed repairs.

 

Once the area of the floor to be replaced has all been removed, the next step is to prepare the area for installing the new floor. If the area has a wood–to–wood joint such as an area in the middle of the floor or any area that does not attach directly to the hull itself, that joint will have to be a scarf joint – ideally at a 10:1 ratio. My only scarf joints went from left to right behind the passengerFloor2~1.jpg (89054 bytes) seat and up and around the front of the driver’s seat. Scarf the appropriate joints in the existing floor using a small hand grinder with a sanding disc or something similar. Any smooth fiberglass surfaces must be scuffed with 80 grit sandpaper. Make sure all surfaces to be joined are cleaned of loose material, dirt and oil or grease.

 

Using " marine plywood, cut to size the necessary wood to fit the area to be replaced keeping in mind any scarf joints that have to be made. After the new floor has been cut out, test fit and make changes until the floor fits correctly. If the floor is being replaced back near the transom, remember to leave a square opening for water to drain and to install a bilge pump if desired. Also, if the floor is going to butt right up to the side of the hull as pictured, a small gap is allowable because it will be filled with West System epoxy. Before starting to install the floor, make sure you have the following supplies:

 

  1. West System #105 resin and #206 slow hardener

  2. West System #403 Microfibers and #406 Colloidal silica fillers

  3. West System # 810 fillable caulking tubes (2) and caulking gun

  4. West System # 800 roller covers (2) and paint roller

  5. Woven fiberglass cloth: 6oz.

  6. Acetone

  7. Paint brushes

Read over the following steps and become familiar with the timing before beginning. Prepare the underside of the floor for installation by wiping it clean with acetone. Also, cleanFloor3~1.jpg (78472 bytes) the mating surfaces in the boat with acetone. Mix up some straight resin and hardener with no fillers. First, using a brush, coat the edges of the wood with epoxy, then using the paint roller, roll on a thin coat over the entire floor (this is to seal the wood.) When this first coat has reached it’s INITIAL cure, mix up another batch and apply a second coat. Initial cure is when the epoxy is no longer workable and no longer feels tacky but can still be dented with a thumbnail. Because the mixture has not fully cured, the next coat will still bond chemically to it. After applying the second coat, immediately wet out the corresponding areas in the boat where the floor will be attaching. Don’t forget to wet out the top of the stringers if the new floor will be covering them. As the second coat is nearing it’s initial cure, start preparing your next batch of epoxy. This batch will have fillers added depending on the type of joint. For a wood–to–wood joint, use #403 Microfibers. For a wood–to–fiberglass joint, use #406 Colloidal Silica. For wood–to–wood joints, thicken the epoxy mixture to a consistency of catsup using the Microfibers, and brush a layer onto the appropriate areas of wood in the boat. For wood–to–fiberglass joints, thicken the epoxy to a consistency of catsup using the Colloidal Silica. Brush or use a caulking tube and apply a layer over the appropriate fiberglass areas in the boat. Make sure all surfaces are completely covered with enough epoxy so that there will be a little squeeze-out when the surfaces are put together. Place the new floor in position and weight it down. Clean off any squeeze-out that is present. Also at this time, if there are any gaps around any of the edges, fill them in using the thickened mixture and the caulking gun. Let the epoxy fully cure.

 

The next step is to finish off the outer surface of the floor. Any exposed areas of cured epoxy must have what is known as the "amine blush", which is a wax-like film, removed. This film must be removed any time an additional coat of epoxy is to be applied over a fully cured coat, or proper bonding will not result. The easiest way to remove amine blush is to wash the surface using water and an abrasive pad. Dry the surface with paper towels before the dissolved blush can re-dry on it. The surface area should have a dull look to it. Any remaining glossy areas can be sanded with 80 grit sandpaper. The wood must be sealed and the joints between new and old must be covered with at least two layers of 6 oz. cloth extending at least 3" out from the joint. The epoxy mixture for this procedure is "straight" – no fillers added. For my boat, I started by wetting out the surfaces along the joints. Then, I laid down one layer of pre-cut strips of cloth over the joints. This was followed by brushing on more epoxy over the cloth and working it in so that the fibers of the cloth were thoroughly saturated. Once this epoxy reached it’s initial cure I started on the next coat. Beginning at the back, I started to apply a coat of epoxy over the entire surface. This resulted in wetting out the main area as well as starting the second coat over the joints. As I went along, I laid down a large layer of cloth (this had been pre-cut) over the entire area, including going over and slightly beyond the cloth already over the joints. Again, this provided a single layer of cloth over the main area and a second layer over the joints. Epoxy was also applied over the cloth – working it into the fibers. Once this step was completed and the epoxy reached it’s initial cure, another coat was applied using the paint roller. One more coat was applied in the same way.

 

After the epoxy had fully cured, the job was completed by painting the parts of the floor that would not be covered by carpet. Besides making the floor look better, the paint would provide UV protection for the epoxy. Once again, remove all of the amine blush. Sand the surfaces smooth if desired. Final sand with 180 – 220 grit to improve paint and carpet glue adhesion. And finally, paint the exposed areas of the floor.

 

If anyone has questions, feel free to e-mail me @ gnhhydro@aol.com.

Floor4~1.jpg (58557 bytes)

 

 

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