How to Set Up a Daybed with Trundle | Frame-First Assembly

Assembling a daybed with trundle looks more complicated than it is. The sequence that works across every manual we checked is simple: build the main daybed frame, build the trundle separately, then roll the trundle underneath. The mistake most people make is treating the two pieces as one project. They’re not. Each frame assembles on its own, and they only meet at the very end. Whether you’re working with a Little Seeds Arden Upholstered Twin Daybed and Twin Trundle or a model like N708P326315/N708P326316, the order stays the same.

Assemble the Main Daybed Frame First

Start with the bed itself. The main frame is the structural base, so it comes together before anything else. Lay out the side panels and the back panel, and join them with the bolts provided. Attach the back panel so the bed has its support wall, then square up the frame by checking that the corners sit at right angles.

Install the slats next. These are the horizontal boards that support the mattress, and they are structural, not decorative. Manuals like the one for Models N708P326315/N708P326316 make clear that slats must be placed on the runner boards and secured with the specified screws. Skip this step and the mattress has nothing solid to rest on.

Here’s the catch that saves you time later: do not fully tighten anything yet. Leave the bolts finger-tight until every piece is in place. A frame that is already rigid will fight you when you try to align the trundle rails. Once the slats are secured and the frame is square, go back and tighten all the bolts fully.

Build the Trundle Separately

The trundle is a second, smaller bed on wheels that lives under the main frame. Assemble it on its own, away from the daybed. Its frame goes together the same way — side pieces, end pieces, and bolts left loose until you square it up. Then add the trundle slats and attach the casters or rollers.

Pay attention to where the rollers sit. The source manuals, including the one for SKU FU105T-1, show that the casters must align with the runner boards or slat positions. If the wheels sit even slightly off, the trundle will drag or catch when you try to roll it. Seat each caster properly, then tighten the trundle’s bolts.

One detail people forget: remove the packing material before assembly. One manual specifically instructs removing the nonwoven material behind the back panel. Fabric or foam left in place can block the trundle from sliding underneath, and it looks like a defect when it’s just packaging.

Slide the Trundle Under the Daybed

With both frames fully assembled and tightened, position the trundle at the foot of the daybed so its wheels sit on the floor, then push it underneath. The manuals describe this step directly: “Slide the assembled trundle bed into the main daybed frame.” One document even lists the final step as “Push Trundle under the bottom of Day Bed.” The trundle should roll in smoothly and sit flush against the main frame in the lowered position.

When it’s in place, raise and lower the trundle once to confirm it clears the frame and locks properly. If it sticks, check the roller alignment and the slat positions before doing anything else. A trundle that won’t slide smoothly almost always means a caster is off its runner board, not that the hardware is wrong.

The trundle and daybed are a matched set. Trundle systems are designed for the specific model and frame they ship with, and swapping a trundle between unrelated models is not supported. Stick with the parts that came in your box and the assembly stays straightforward.

The final tightening pass matters. Go back through every bolt, including the ones holding the slats, and snug them down once the frame is square. A daybed that is assembled loosely will wobble, and a wobbling frame transfers strain to the trundle’s casters. Manuals for models like the Little Seeds Arden Upholstered Twin Daybed and Twin Trundle state plainly that the daybed is ready for use only after all assembly is complete.

If you’re still deciding which setup to buy, our roundup of the best daybed trundle options compares frame quality and rolling mechanisms side by side.