I posted earlier about the plywood rotting in my Merhow trailer walls.  First guy told me that it isn't worth fixing. I've been looking online at used trailers and noticed a lot of older trailers with plywood on the inside of the walls. I was wondering if it would be possible to have someone attach new plywood to the fiberglass on the inside to fix this problem? Would it be safe to drive? I am having a hard time finding a used trailer that I can afford.  I really need one for short trips...there is no riding arena at the barn I board at. Thanks!

I'd venture a guess that most plywood/OSB is fastened to the inside of trailer the prevent kicking damage...and adds no structural support.

I was once at an RV dealer where they were in the process of replacing and FRP side on a Class c motorhome. The new sidewall, from the rear to the overhead bunk area, arrived in one piece via truck. It had all the opening routed out. Big job considering all the interior cabinets had to be re-mounted, plumbing, heating, appliances.

Big job, but then the mfg was paying.

Your trailer isn't worth what to whom? How much will it cost to replace it? If the repairs are less than a replacement, would you keep it?

The answer is yes it can be repaired. The unknown is how much damage is involved, and what the resulting repair costs will be. Screwing plywood to the inside of a delaminated panel is akin to placing a bandaid on a broken limb. It will add even more weight to the already heavy trailer and offer little or no structural improvement.

Without getting technical, a FRP repair with a plywood core involves a few steps. If the delaminated areas are small and don't involve a whole panel, they are identified and marked. On the inside, a trim router with a straight bit cuts away the interior FRP of the involved area and it is removed. The bit depth is set so that it does not contact the exterior FRP skin. The rotted wood is removed, and a new carefully crafted piece is fitted and epoxied in place and to the outside skin. The inside FRP skin is replaced and the whole wall is then painted to match the original. The outside skin is left intact and undisturbed, to maintain the original looks and integrity.

Any marina that offers fiberglass boat repairs can effect your trailer repairs. Repairing cored fiberglass construction is a common practice for these businesses. Most boat yards in the NE command at least $65-$75 shop hourly rates plus materials. Again in the NE, around the middle to the end of Oct., many boatyard labourers will receive layoff notices. Their wages are typically in the ~$20 range. Many of them welcome under the table jobs at those rates.

Your repairs could range greatly in price, depending on their volume and numbers. Even if they approach the thousands of $ range, can you purchase a replacement trailer for that amount?

You need to talk with and show your trailer to, someone who is competent in these types of repairs, so you can make an informed decision. BOL

figero-I never thought about that...I am about 6 hours away though.

Does anyone have an idea of how much this would cost to do? I know the real answer is "it depends!" but to me it sounds like a fairly expensive, involved repair.  I am wondering if my money would be better spent finding a decent used trailer??

Unfortunately, I can't see Merhow helping me out a great deal.  I bought this trailer new in 1993. I had several structural problems with it beginning 3 years later (and a year after the warranty expired.) I called Merhow at that time and basically they told me I was out of luck. They were not even willing to cut me a deal on the repairs it needed. Horrible customer service.  I know someone now who is now going through the same type of issues with a new big, expensive custom Merhow she just bought. 

It just seems to me that Merhow does not stand behind their products.