It depends on where you are and what kind of shelter you need from the elements. In the tropics where palm trees are plentiful, tiki style huts and
thatched shelters can be made to withstand some serious storms and stay dry if built properly. I've helped stand and thatch a few that withstood
hurricane force winds with only minor loss of thatching.
Here's an idea:
And how about adobe and/or rammed earth?
Another thing that you can do if you've got access to some sort of mortar and lots of chopped and split wood is make a chordwood cabin. Basically
it's a stack of split logs with mortar between the wood. It's a lot less technical than building a log cabin and the materials are small enough
that they can be handled easily my anyone, skilled or unskilled, safely.
How about using stones? Around here it'd be REAL easy to build a small stone cabin. as there's plenty of rock around here and lots of it is
already flat enough to stack up into walls that will stay put, especially when i mud it all in with some sort of adobe or mud/grass mix. I'd make
sure i built a stone fireplace that can be used for cooking and then i'd most likely use agave stalks and a lattice of ocotillo to tie bundles of
beargrass to and thatch a roof.
It really depends on where you are, if it's cold enough you can carve you an ice palace.
Whatever you do, keep it simple and practical. A small log cabin big enough to cook, sleep, and work on crafts and projects is practical. A 5
story log mansion with balconies on every floor and 100 rooms os just ridiculous.
And resources, what do you have to work with? If you have concrete or can make it, then that's a big plus. Limestome heated in a fire and then
cooled will give you lime to make concrete with. Add water to the lime and it'll react, dissolving into a putty. This putty is what you add sand
and rocks to and you've got concretre Just add sand only and you'll have mortar.
If you can build four equilateral triangle flat pieces you can put them together into a pyramid.
If you're on the beach in south america or mexico you may be able to build a structure out of whalebones. The ancient Peruvians did it that way.
How about a large teepee? Buffalo hide isn't as easy to come by ever since white man "discovered" america, but i'd be willing to bet that if
it's post doomsday, there'll be "feral" cows roaming around. Cows are a LOT easier to "hunt" than buffalo.
Several tribes in the southwest deserts were cliff-dwellers, and should you find yourself in a place that lends it to this type of architecture, that
may be an option as well.
Underground and semi-underground are also possibilities depending on where you are and what you have to work with.
Got bamboo? Check out how the polynesians and pacific islanders build a raised floor out of laminated bamboo. If you've got bamboo and a
machete, then you're all set.
How about society's waste? Come across something like a supply of pallets? There's a modular prefab home right there. Even without nails you
can lash 'em together and build a structure.
My point is that there's a LOT of ways to build a few walls and a small roof. Use what you've got to fill your needs. In the tropics you won't
need (or want) to cook indoors as you would in say, alaska. The same with insulation, in the tropics thin walls are fine but you'll want more
insulating materials in colder regions.