At first it was a matter of looking at the floor in the house – were they concrete or timber supports? The room that would take our books had timber supports so we could only look at running shelves across the supports (to spread the weight). It turned out that pine which was the cheapest material, was also the best material. Its weight to support ratio was super (still is) and a few of the most basic tools ran up our first shelves. I used right angle support brackets at the sides to support the shelves – again cheap, but also the 90 degree angle on the bracket kept the shelves straight!
The books themselves hid the brackets for the most part so we were up and running. I was very happy to see the wall filled with the books collected from boxes, under beds, attic, stacks in corners, kitchen, cupboards, drawers and bags.
My mistake was the coating I used to paint the timber. Both myself and my son are asthmatic, so I now use natural oils and wax. I am not sure what you think of those coatings, but they work well, look great and if ever I throw them at the bottom of the garden – they will not poison anyone. The oil I use the majority of the time is linseed oil (boiled so the drying time is reduced by 50%) and the wax is from a Lady who lives back up the mountain who has hives. She mixes it with turps and tins it for sale (she doesn’t charge enough). It is hard wearing and has a lovely finish, but remember it requires a large amount of hard polishing – like a titanic pair of shoes.
Do not be afraid to try making your own shelves – books will always make a shelf look good and here is something I saw somewhere recently (please let me know if you know where its from) – “The Arc was built by amateurs, the Titanic by professionals”.