I have an old mattress foundation:Box frame of 2×4s. Has 3in layer foam over cardboard over 1×2" slats 5" apart. I have attached a photo of the underside.
The best thing you could do is to remove the foam and cardboard and buy 1 x 3 slats to go between each of the 1 x 2 slats. This will reduce the gap between the slats making both the cardboard and foam unnecessary and stronger. Home Depot carries 1 x 3’s but you would have to cut them yourself. Nails or drywall screws work good to secure them in place.
Thank you,Ken! Although a spring mattress is on it now,if we add the 1x3s will it be suitable for our latex mattress? (with the wavy dunlop topper your previosly recommended,and I purchased,thank you!)
Absolutely, you’ll never have to worry about it again if you add the extra slats I recommended.
