Fiberglass Roofs (Roof Replacement Tutorial- Part 2 )

If you are looking for part 1 of this topic, feel free to go here. Today we will continue the discussion about fiberglass roofs and kind of a “do it yourself” tutorial.

Place on another section of trim, bring up the edges again so that they sit together nicely and keep marking and cutting in the same fashion explained in part 1 of this subject. It’s always nice to mark and cut one trim where it meets another. This is purely for aesthetic reasons only. It may not be important two stories up but if your roof is at low level and possibly visible from an open window, you may want to do this just to make it look nice. When all the courts on the miter joints look right, secure the trims into place (again without bashing the nails all in.) Now it’s a matter of working your way around repeating the process until the whole bay roof is pinned into position. Once everything is in place, you can nail the trims down fully and put in the rest of the nails.

Now it’s time to form your rope stand on to the rear fascia. On a very small roof, there is no real need to worry too much about expansion gaps. I would simply allow something like 10 mm behind the trim and up against the up stand. Once the wall up stand is complete, nail all PU adhesive into position. Ready for taping the joints but do not fix it into the rotten facial behind as this will not allow it to be placed at a later stage without damaging the fiberglass roof. Good quality duck tape is quite acceptable on small roofs. On larger projects 100 mm fiber glass bandage would be used instead to strengthen the joints.

Now clean all the trims with acetone and a clean rug ready for the matting and resin. This removes any grease or contaminants so the resin, bonds properly. If you have any smooth bits on your trims, give them a light sanding. Having measured the roof caught the fiberglass matting, I like to use 450 gram as this is what I use on the majority of my projects. Simply measure, mark and cut with a decent set of household scissors. Make sure you lay the matting in runs going from front to back and overlapping the joints by 75 mm (roughly) and the edges of the direct rims by about 10 mm. This will help to protect the face of the trims from dipping resin. The tools and the wood are simply ballast to stop the matting from moving or blowing off. At the rear up-stand against the facial, I’ve allowed enough return so any edges of matting are covered by the roof tiles when they go back on.

Again, for nice aesthetic finish, rip the edges of any overlapping joints. This will stop the appearance of visible lines, when the roof is finished. Simply pull the edge of the matting firmly and it will break away. Before you mix any resin, lay out all of your equipment first so it’s ready (most importantly safety goggles.) Never use any hardener or resin or top coat without full wrap around eye protection. Add catalyst to the resin. If you are new to fiber glassing, never mix over 4 litters at a time especially on a small roof. I like to use a syringe to add my catalyst, I finally can square the hardener underneath the surface of the resin, making it faster and easier to mix.

My advice on resin application on a small roof is to pour it on top about half a litter at a time. When you move the resin about with the roller it will travel through the matting quite easily. There really is no need to wet the deck underneath on a small roof. Use the brush with a jabbing motion to press the white matting into any details (tricky corners.) Use the roller whenever possible as this moves around, the resin quite easily pushes any air bubbles that may get trapped. I would suggest on nearly all fiberglass roofs using standard 50 grand matting, you should use two liters of resin per square meter as a covering guide. This will you an idea of covering thickness, helps to stop air bubbles forming and pin holes caused by dry spots. Because we went over the drip trims earlier with the matting, we can simply roll around the edges without fear of too many drips. Up-stands and verticals can be done by rolling any resin into the corner and then uphill. Next cut some matting patches to wet up with any remaining resin so that we can strengthen and waterproof the the miter joints on the drip trims. Using the two inch brush with the same jabbing motion as earlier, paint the matches underneath all of the miter. This is now your roof completed and it’s just a mater of waiting for it to harden.

If you time it so the resin has dried just beyond the waxy surface feel that it gets, trimming the edges with a sharp knife will be very easy. If it hardens off too much it can be still done, but a more robust handed approach will be required. Now wait until the surface is hard enough to stand without fluffing up or blocking the grid or sand. Lightly sand off any high spots of rough edges on the new roof. This isn’t necessary for any other reason than to give a nice finish. As long as you apply the topcoat in under the first 24 hours. Once sanded brush the dust and we are ready for the top coat or color. The two most common choices being light gray which looks a lot like seasoned led and dark grey which has the look of new bossed led.

Temperature will dictate how far and how easily your colored top coat will spread. In warmer weather, the top cote slightly will ruin so 1 liter of color will probably cover between two and three square meters. Don’t mix too much at once however. Using the same technique as with the resin, deposit about 1/4 of a liter of color onto the bit and work it with the roller using the brush to finish any details. The roller can also be used on the edge of the drip frames and will leave a superior finish.

Don’t worry about the overly shinny appearance and the fact that you can see the matting underneath. It will quickly fade to a much better finish. Within twenty minutes you should see how the top coat hardens.

And this completes the tutorial on fiberglass roofing. If you follow step by step everything I’ve outlined for you, you should be able to get this going with no great inconvenience. It’s not really that hard, once you do it once or twice. Come back tomorrow for more fun tips and great information on fibers.