PaperMan & Kaelus
Kaelus
Got a minute to crunch some numbers on a simple shelter design? I’m looking at the minimal material load that still gives full protection from the elements. Could use your knack for precision to tweak the angles.
PaperMan
Sure thing. For a basic pitched roof you want a slope of about 30 degrees for rain runoff, that gives you a decent balance of material and weight. If you use a triangular truss design, the load on each member drops by roughly 25% compared to a flat roof because the weight is shared along the two legs. If you go for a gable, keep the wall height to about 1.5 times the roof slope angle—so if the pitch is 30°, walls about 45 cm high for a 1 m span. That keeps the overall surface area low, reduces material, but still blocks wind and rain. If you need an ultra‑light version, try a geodesic dome approach with small triangles; each member gets less than 10% of the total load. Let me know the exact span or any material constraints, and I can fine‑tune the angles.
Kaelus
Thanks. Let’s say the span is 1.2 m and you can only use timber with a compressive strength of 30 MPa. A 30‑degree pitch gives a roof length of 1.4 m per side. With a triangular truss, each leg carries 25 % of the total load, so each member needs to support about 7.5 % of the roof weight. That translates to a cross‑section of roughly 40 mm by 40 mm for a 12‑mm thick plank, which keeps the weight down while staying within the strength limits. If you can tighten the pitch to 35°, the load per member drops to 6.5 % and the plank can be 35 mm square. That’s the rough math. Any other constraints?
PaperMan
Just check a few more things before you set it up. Wind pressure on a flat side of a 1.2 m span can add a couple of kilopascals, so make sure the 40 mm or 35 mm cross‑sections can handle that plus the dead load. Also look at deflection limits – you don’t want the roof to sag more than a few millimetres under a full snow load if you’re in a colder zone. Lastly, make sure the timber you choose has a good durability rating for the climate you’re in; a 30 MPa figure is good for strength, but if it’s exposed to moisture you might need a treated or naturally rot‑resistant species. Let me know if any of those apply.
Kaelus
Check the numbers – a 40 mm square or 35 mm square section can handle the extra wind pressure if you keep the wood grade at 30 MPa, but the deflection under a full snow load should stay under a few millimetres. For that you’ll need to make the joints tight and the truss braced with diagonal ties. If the climate is damp, treat the timber or use a naturally rot‑resistant species; the strength stays the same but the life expectancy will go up. Those are the main points to lock in.
PaperMan
Sounds good. Just double‑check the joint details and make sure the diagonal ties are sized to keep the whole truss stiff. Once you’ve got the plan nailed down, you’ll have a clean, lightweight shelter that still holds up to wind, rain, and snow. Happy building!