Manufacturing stringers from glued plywood and MDF

[Henrik Eriksson]

I have plans to build a staircase myself. I have read countless threads advising against buying a staircase, but I have decided to give it a try.

I have looked at glulam, but since I want to make a staircase with an underlying stringer, it will be about 400 mm wide to cut out for the steps. Therefore, I have considered gluing 3 pieces of 12 mm plywood myself and then covering this with 6 mm MDF (to get a nice finish for varnishing).

What do you think about the load-bearing capacity of this construction? Is strong pressure needed when joining the plywood for this to be sufficiently strong, and if so, do you have any tips on how I should achieve the necessary press? I only have access to clamps.

Grateful for any help!

 

[MathiasS]

Isn't it reasonable to buy ready-made kertobalkar for this? Probably doesn't cost much in the grand scheme of things? Of course, not an option if you really WANT to build everything yourself...

 

[Henrik Eriksson]

It's not about the money. I didn't know it was called Kerto beams, but I was thinking that the product should exist. What I'm questioning now is just how the surface finish will turn out when spray-painting Kerto beams. I only found 45 mm Kerto, and if I cover them with 6 mm MDF, the beams will be 57 mm wide, which I think might be a bit thick.

Then I wonder if I'm on the right track? Is it reasonable to build stringers from that material?

 

[prototypen]

To glue this, you should have a glue press, but these are fairly large pieces.
But the pieces will probably be quite long, if it's a full-floor staircase, it will be around 4 meters, and then it's likely impossible to get ahold of a glue press.
But if it is 4 meters, how do you splice the plywood? Does the load-bearing capacity only count as 24 mm?

If you continue with the glulam approach and glue on triangles for the steps instead of cutting away?

Protte

 

[katos]

Curved stringers are made in laminated plywood so it shouldn't be a problem. I wouldn't buy construction plywood but at least structural plywood or maybe birch plywood. Screw temporarily while the glue dries and then remove them. I would consider having the grain in the board parallel or 90 degrees with the stringer. It will become really stable.

 

[Henrik Eriksson]

Thanks for all the tips! I might have added that it is a U-staircase with cut corners. So the longest stringer will be 1.8 m.

I spontaneously feel that this must be stable, but I wanted to get someone else's perspective on it.

Thanks for the tips on screwing together! Since I'm planning to cover with MDF, the holes are no problem. But how close can I screw without compromising the strength? This should provide enough pressure, so I can skip the clamps.

Regarding glue, it's PU glue that is recommended, right?

 

[prototypen]

PU glue has the characteristic of foaming/expanding and requires higher pressing pressure/closer spacing between screws/clamps than regular white glue. Use regular white glue as it is indoors and a dry location.

Protte

 

[Robert-san01]

Feel free to start a build thread if you decide to go ahead with the construction. I'm also considering making a staircase myself with underlying vangar.

 

[Henrik Eriksson]

Promise a construction thread when I start. Thanks for the help!