After a lot of Messing about I´ve got the last two pics uploaded.
Basically, if you can measure and cut at a right angle..it´s easy.
First of..what do you Need? For the structure (walls) I use 1cm thick insulating foam. It´s cheap and one pack should allow the creation of dozens of buildings.
Then some fine dry sand, some PVA glue, a sharp knife, right angle, some board Pins, a pen, corrugated paper from a biscuit packet (or similar) and some normal dress Pins, some card (Cereal packet or similar) and a ruler.
Yes..the PVA is in an old washing up liquid bottle..it´s easy to use and the cap doesn´t get all clogged up which means an airtight seal.
Paints I use are cheap acrylics, the sort used for painting walls. You´ll need White, chocolate Brown and red and a 1" Paintbrush.
This building will be a Taverne with a small storehouse attached but after making a few your Imagination can lead you anywhere, curved arches, complicated roofing with Loggias, balconys and and......
Mark up and cut out the wall sections. For marking out the pattern, don´t use felttip pens or biros with blue ink. They can write easily on the polystyrene but the ink bleeds really badly into the PVA - sand mix and later bleeds into the paints. I found this out when I made the Roman baths. I had to glue tinfoil over the effected Areas, then cover that with sand and PVA mix to seal the ink in. Okay, I found a solution but it wasted time.
After prefitting to see if the wall sections match up and the building looks square, glue them together. The Dress Pins are used to hold the parts in place as it drys. I´ve recently found out that toothpicks are also good. A short length of one pointy end and then push it in completely. This doesn´t work where there are openings like doors etc but the toothpicks hold way better than the Pins.
When it´s dry, remove the Pins (in the case of toothpicks they stay put) and smear PVA over the walls (just a thin layer) and sprinkle fine sand over them. As can be seen, I´ve added a floor to this one. This building will have a removable Roof so the floor is necessary but in general the flooring doesn´t have to be added.
As the flooring is made from the same 1cm polystyrene it means the door will end up higher than the outside floor and steps will have to be added. As I´d planned to add a floor I also made the doorway 1cm higher to take this into account.
When the sand has dried, paint.
Another step, window and door Frames. Like the flooring, these aren´t necessary but it adds to the General look of the finished building. These are simply made from coffee sticks, cut to length, the top and bottom of the Frame glued in first, then the sides. Any small gaps can be filled by putting some PVA on your fingertip and smearing it over the cracks. The easiest way of placing the pieces of coffee stick is to use an old pair of tweezers.
Now the Roof. Thin Card folded and cut to shape. Put PVA along the top of all the walls and then attach the Card, Holding it down with the board Pins. It´s best to start the pinning down from the top of the Roof and working down to the bottom.
The tiles. On the left is the back of the corrugated paper which is first marked off (on the back of the sheet, not the corrugated side) in 1 cm strips. Then paint the corrugated side with chocolate Brown paint. It´s best not to paint the whole sheet in one go but cut it in half because as it gets wet it warps and you can cover half of the sheet faster before it warps than the whole sheet.
When the corrugated paper has dried cut it into strips. Simply apply glue to the back of each Strip and attach, overlapping each new Strip a tiny bit over the previous one. It doesn´t work as well if the glue is just smeared on the Card as the overlap doesn´t attach properly to the previous layer.
Finally the tiles for the top of the Roof. These are made with 0.5cm wide strips of Card cut into lengths of about 0.8 cm´s. Each one is then curved lengthways over a Paintbrush handle.
Keeping hold of the Paintbrush, dip the end of the handle into some PVA, smear it under the tile and attach. It´s a good idea to keep a tissue handy to occasionally wipe off any excess PVA from the Paintbrush.
When it´s all dried, paint with chocolate Brown, then let it dry (a hairdryer Speeds this up) and dry brush firstly with mix of brick red and chocolate Brown, then a final drybrush with brick red.