high bed project for box room

hi everyone!

i'm thinking of making a high double bed in the box room, very simple construction. 2 timber beams on opposite walls, 2 or 3 thick planks spanning these beams, and finally floorboard thickness planks resting on these last planks with gaps in between on which the mattress will lie. ( i'll get round to doing a diagram when i can figure out how to use these cad 3d software!)

questions:

1. for the 1.4m beams which are going to be anchored to the wall, what size should they be, considering a maximum load of 200kg? i was thinking maybe 5"x2" or 4"x3".

2. what fixings should i use to anchor them to the wall? one wall is an external brick wall, and the other wall is an internal block wall. i was thinking of sleeve anchors, or should i use shield anchors? or maybe these are both overkill and large plugs and screws should be strong enough? also, how many should i use and what size?

3. for the 2m planks spanning the beams, is 1.5"x4" strong enough for the span. if i have to increase the size, ideally i would like to keep the thickness fixed and have the width as variable.

any tips are appreciated. thanks.

I'd go for a simple "box" as the main frame.

So you'd have the two beams opposite each other, and then two beams at right angles, pushing those beams against the walls, so theres no chance of the wall anchors shearing out. They'd have to snap, which is less likely.

For the anchors, I'd use a threaded rod and resin times 3 or 4 on each beam. Though it depends on the wall, you could get away with shield anchors.

With one cross-beam at each side, I reckon you'd only need two in between those to support the weight.

Finish it underneath with a ceiling and a light (though plasterboard may need a little more support than that above).

5x2 should do it throughout.

Wait for the experts to confirm everything though lol.

Its something I've always wanted to do to be honest.

Dont forget the ladder!

thanks for the advice steve.

i like the idea of the box frame.

and the tip for using the threaded rod and resin. probably the only choice for the internal wall as i think it is breeze block behind the plaster.

as for the ladder, well that's going to be the easy bit