Wheel Well Boxes and Landing

Building something complex like a house involves long series of "Have to do X before you can do Y, have to install Z before you can do Y, have to finish A before you install Z..."

I've been battling my way through such a sequence toward the end goal of installing the siding. Before I can install the siding, I need to install the door--thus completing dry-in--and its trim, and before I can install the door, I need to finish the wheel well boxes and entrance landing, to provide an elevated floor for the door to sit on.

And that landing is finally done!

All I knew about the design of the landing was that I wanted it to have cubbies around the edge to store shoes. The top of the floor had to come level with the top of the wheel well arch header. And it had to be separated--physically and thermally--from the exterior.

The most immediate problem had to do with that last requirement. The problem was: oh, look, big holes. The way the trailer is designed, there is a gap between the fenders and the width extending flange. It's a funny gap, about 1 1/2" wide, and tucked away in the corner of the wheel well/wall structure. I toyed with the idea of a plywood gap-closer, but Dad had a piece of flat metal flashing and suggested I use pieces of it, instead.










Thanks, Dad!

I bent the flashing into a U shape using a piece of 2x2 lumber...











...And then glued them into place across the hole using a whole lot of glue and caulk to seal every possible little gap.

Ah, what elegance, refinement, grace...

Then I proceeded to build the rest of the box.

I build a fairly basic box around the wheel well that will be under the kitchen counter, using 2x2s and not-quite-2x2s left over from 2x lumber I ripped for other purposes.


I glued and screwed 1/2" plywood (left over from the roof) to close in the sides, then squirted about 2 jumbo cans' worth of Great Stuff expanding foam insulation into the nooks and crannies.



 My idea was to seal up any remaining air gaps and get extra thermal insulation around the exposed metal of the wheel well. Spray foam is great for vulnerable areas like this, because it conforms to its container, is an excellent thermal insulator, and resists all kinds of decay (yay, petroleum products...).   

I would have loved to fill the whole box with spray foam, but those cans don't really hold all that much--plus, I had an entire package of Roxul rock wool insulation left over from the floor.

Rock wool is a decent thermal insulator and is similarly decay-resistant, in case moisture condenses out at the meeting point of hot and cold. Plus, it was available, and at this point, "free," unlike additional cans of Great Stuff that I would have had to buy.


As when I used it before, in the floor, I sawed the batts into suitable sizes (the 5 1/2" thick version for 2x6 construction worked great, each 15 1/2" batt sawed in half lengthwise) and stuffed them gently into the box. Insulation material doesn't insulate as effectively when it's compressed, so gently is key!

The wheel well box on the door side of the house was a little more complicated. I constructed it essentially the same way as the other box, but it's bi-level, since the landing has to be a little higher than I was building the box full of insulation. I also used 3/4" plywood, for extra weight-bearing strength.

The really complicated part came when I started to build out into the room to create the landing. The landing construction relies a lot on the strength and stiffness of 3/4" plywood--which is considerable--to provide the load-bearing support for the 3/4" plywood floor.

As you can see in this photo, the frame of the landing is composed of a series of interconnected boxes. Short lengths of 2x2 provide nailing, corner reinforcement, and cohesion between pieces of plywood. I made sure to make all the corners square and pieces plumb; the only problems came about due to irregularities of the original base subfloor.

Perfectly. Frickin'. Level.

I actually ended up with a landing that is perfectly level from side to side, but which slopes slightly away from the door opening. I'm going to call that a feature: after all, you don't want the inevitable landing puddles to flow toward the door and under it and rot out the threshold, right? Right? Much better that they flow away from the door, into the room, to be mopped up!







Anyway, here's another shot of the final product. Oh, yeah.

Just to recap the functionality: It has five cubbies, each 9" wide by 12" deep--the perfect size to completely enclose even my clunkiest hiking boots. It's about 11 1/2" high, which is low enough to step up and down easily, but high enough to make it a nice place to sit and take on/off your shoes. And in case you missed it in the third photo from the end, there is an electrical outlet in the side facing the bed.

It will, of course, have trim and prettiness when it's finally finished. For now, the most important thing is that it's there, and now I can install the door. Hurray!