Trailer for 7??

[bictonboys]

Hi. I am currently finishing off a project I started a few years ago, a utility trailer. Naturally my thoughts have strayed on to what I’m going to waste the next two years of my spare time doing- build another trailer? Yes. This time my design parameters are a bit different- I’m thinking a square drop style build with an up and over hatch door at the rear. This door will serve as the entrance to the accommodation . The interior will be a ‘day van’ style layout - bench seat surrounding with a table in centre. The trailer is not primarily for this purpose,but should be able to provide sleeping arrangements for two adults and five children if required. A pull out at the front will provide storage and/or kitchen.
Despite advice to the contrary I have decided to build the structure separate to and prior to the chassis . The frame will be 3x1 spruce/larch/ash skinned with exterior grade mdf with seems filed and taped. Due to the layout there may not be many windows.
This may be a slow starter due to me working on my other trailer still-stick with me!
Cheers

[Pmullen503]

Take whatever materials you plan to frame with and submerge then in a bucket of water for a week. If they survive, use them. If not, don't.

I'd be concerned about MDF. How rot resistant is it?

I had a small area around a door that had a layer of underlayment that delaminated due to water intrusion after about 5 years. It was a huge PIA to repair. This time I used marine ply. I wish I had spent the extra money originally for the right materials.

[bictonboys]

Yes I appreciate your concerns-I am in 2 minds about using this mdf product-partly due to the price also as it is more money than marine ply. Having said that I’m keen to try it out ,also the smooth finish of mdf would be a big plus when it comes to paint finish- although I plan to paint the bottom third in bed liner anyway.
I’m happy that my framing materials will do the job,especially larch-it’s pretty bulletproof in my experience.
Have you seen this before? - medite tricoya extreme - it’s the water proof mdf- some one on utube has done the experiment with good results

https://youtu.be/GIiD6VLtcHw?si=0VYds1-Ykcs8SM2u

[Pmullen503]

There are a variety of MDF products from cheap to exotic. There are some MDF products used for outdoor signs that are indestructible, but very expensive. Some cheap shelving material disintegrates when wet.

As long as whatever you use won't disintegrate or rot the first time it gets wet. Sooner or later water will get into some crack or gap. Hopefully, your materials will resist rot long enough for you to notice the problem and fix it.

[bictonboys]

As you say -water intrusion causes problems-even the expensive panels will fail eventually,so I suppose the top priority is sealing doors windows ,hatches,corners etc well- I,ve been going through the build posts on here again to educate myself. One thing I was looking for which I haven’t found a lot of is ‘homemade’ windows. I was thinking of putting windows along the top edge of the structure- similar to a VW samba- i wonder if it would be possible to use toughened glass in timber frame- my worry is they would be hard to seal- especially if they were on a 45 degree bevel

[Pmullen503]

Imagine your trailer in a car wash or a hurricane (because towing at 70mph in a rainstorm is like that) and think about where water might get in.

Think about after years and thousands of miles of bouncing around, what joints might start to open up. And try to design in redundancy. Nothing is ever going to be perfect but having a few potential failure points to keep an eye on versus dozens is a lot better.

If you design with the idea that water won't pool or intrude if sealant or joint or weatherstripping should fail. You'll build a longer lasting trailer. A good hatch or door directs water away even if (when) the weatherstripping fails.

Having that attitude while you design things will hopefully give you a more trouble free trailer.

[bictonboys]

It’s not that hard to imagine the trailer in a hurricane after the last few weeks or so here! There are plenty of trees which have come down which I can build this thing from anyway - thanks for the advice -hope to back here with some progress before too long