Why a Lean-To Shelter?
Although a lean-to is time consuming and requires a lot of materials to build, it can provide a spacious shelter. If constructed correctly it can be made to be water proof, a fire can be placed nearby and a reflector constructed to direct the heat into the shelter.

Skeleton
To build a Lean-To shelter, you will need two main up-right supporting members. These can be trees or poles placed into the ground, but using free standing up-rights is the better option. A cross member is also required to go between the up-right and connect to each. Before choosing your location is wise to locate the direction the prevailing wind is coming from, so that you can site the entrance away from it. Wind and rain blowing towards the entrance will take the heat from the shelter.
Once the cross member has been connected to the up-rights, you will need to secure ribbing close together from the cross member sloping all the way to the ground. Once the downward ribbing has been added you will need to apply ribbing which, crosses and weaves through the downward ribs to form a lattice effect.

Top Dressing
Now you need to add the top dressing, this should be a large quantity of vegetation which could be any thing from bracken and fern, to pine branches. The vegetation must be layered in away that will allow rain to run off without penetrating the dress.
This can be done by placing a strip of vegetation along the bottom length to start with. Then move up a level adding the next level in the same way. You must ensure that the new level always over laps the level below it.
Once you have sufficient vegetation in place, you will need to place a layer of light sticks on top to hold the vegetation in place, otherwise a strong wind could strip it all off. Note, you should not use heavy sticks as these would compress the debris and you would lose the insulating properties!

Side Dressing
For added protection, walls can be constructed in the same way.

Inner Insulation
Once the outside is complete, you will need to stuff the inside with the softest, driest debris you can find. Stuff it from top to bottom, crawl inside to compress it, stuff it again. Even if it is wet, this shelter will keep you warm.