Two twin mattresses when laid side by side on an extended ikea daybed are about 5” shorter than a king bed. I am thinking of buying an ikea daybed with 2 thin spring mattresses as recommended, then also getting a 3” king sized foam mattress topper.

The trick is that I’ll add a removable 5” wood extension off the end of the bed so the mattress topper can be laid out at full king size, including with king size fitted sheets. The 5” extension will be raised by about 3” from the height of the bed slats so it matches up well enough with a single thin mattress that’s in use, and have a 3” lip so that it looks good with king size fitted sheets wrapped around it. The 3” topper should also eliminate the feel of a gap between the spring mattresses.

That’s the concept at least. We have tall people in our family and want a real king size guest bed with a thick mattress, and I figure 3” foam plus 5” spring will be real enough. Before I buy everything, has anybody else tried something similar? Is this idea genius or stupid?

Trying to repurpose this daybed instead of storing/selling, but not sure if our king mattress will fit it. Thanks!

We're planning to use it mainly as a sofa in the living room. I have read more negative reviews when it is used a queen/king size bed. I want to hear some positive reviews too! Well, negative reviews are still welcome before we spend our money with this furniture.

Picture is taken from one of the showrooms in IKEA Philippines.