We drilled holes for the bolts for plywood, thru the metal slats. Where you drill can depend on metal location. You try to put bolts in plywood corners for keeping wood flattest, Maybe 1 or 2 bolts between corners on a long piece, but sometimes you have to use other locations for anchor spots.
Bolts are round head, 1/4" threaded part I think. Not very long. Our trailer has two slats above the solid wall, so we went with larger plyood pieces to fill the whole "window" frame under the slats. I think we have about 8 pieces, numbered, to fit on sides of trailer. He doesn't cover the slats on either gate, better air flow in winter. Horses LIKE being cold over being hot. I am always surprised at how fast you can get them sweaty hauling in winter. With the plywood up, that trailer is not drafty unless we open the roof vents. You get some new air from the open slat gates, but not really drafty to chill anyone. Heck I don't even cover horses unless temps are below 45F, when the sides are on trailer. They have good coats, stay plenty warm at those temps and above, just nekkid!
You MUST be able to move the mats, so floor can get air dried after use. Not cleaning trailer and lifting out mats after EACH use, is how floors rot FAST. Corners and edges where wall and floor meet collect moisture, floor always dies there first. We have built in a divider for the front, so we lay mats over that between uses. Lets floor dry well, and all those floor corners and edges are exposed for drying too.
If you have a good size gap under back door, maybe you could get some metal strap welded on like little legs. You weld the 2 or 3 little legs on the door bottom, so they act as stoppers, preventing a hole big enough for mats to get thru. I have 4'x6' mats, so any hole smaller than 4ft, would prevent mat escape. We redid the cattle gate part, made backdoor a solid one-piece, so 3 legs would work if we didn't have the ramp.
Bolts are round head, 1/4" threaded part I think. Not very long. Our trailer has two slats above the solid wall, so we went with larger plyood pieces to fill the whole "window" frame under the slats. I think we have about 8 pieces, numbered, to fit on sides of trailer. He doesn't cover the slats on either gate, better air flow in winter. Horses LIKE being cold over being hot. I am always surprised at how fast you can get them sweaty hauling in winter. With the plywood up, that trailer is not drafty unless we open the roof vents. You get some new air from the open slat gates, but not really drafty to chill anyone. Heck I don't even cover horses unless temps are below 45F, when the sides are on trailer. They have good coats, stay plenty warm at those temps and above, just nekkid!
You MUST be able to move the mats, so floor can get air dried after use. Not cleaning trailer and lifting out mats after EACH use, is how floors rot FAST. Corners and edges where wall and floor meet collect moisture, floor always dies there first. We have built in a divider for the front, so we lay mats over that between uses. Lets floor dry well, and all those floor corners and edges are exposed for drying too.
If you have a good size gap under back door, maybe you could get some metal strap welded on like little legs. You weld the 2 or 3 little legs on the door bottom, so they act as stoppers, preventing a hole big enough for mats to get thru. I have 4'x6' mats, so any hole smaller than 4ft, would prevent mat escape. We redid the cattle gate part, made backdoor a solid one-piece, so 3 legs would work if we didn't have the ramp.
but they were creeping forward. Now I've got mats all the way to the front.
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