How to Make Interior Architectural Columns

Make or buy a mold. Choose a ready-made silicone column shell to produce an ornately-styled structure with bas relief flutes, patterns and embellishments or use lumber, nails and wood glue to construct a simple column shape. Spray the inside of either with a silicon medium so the plaster doesn’t stick to the sides as the medium hardens. If you're on a shoestring budget and want to craft short columns, use a cardboard box. Line the box with plastic sheeting -- smooth it out so you don't wind up with wrinkles -- and spray it with silicone before pouring in the plaster.

Calculate the amount of plaster you'll need for your column by measuring the interior of your mold. Read the box of plaster of Paris to see how much medium you'll wind up with after mixing the compound with water and then buy enough boxes to do the job. Purchase more than you think you need for your column as long as store policy states that you can return unopened boxes of plaster mix if you don't use them. The calcium sulphite in the mix will expand as the plaster of Paris hardens.

Unmold the architectural column(s) after allowing it to cure per the plaster package directions. Use sandpaper to smooth out rough spots or edges on sides, top and bottom. If you discover a hole or crack in the column due to an air bubble that didn’t disintegrate under the weight of the plaster -- or a section of the column that didn’t come out of the mold cleanly -- mix more plaster, fill the hole, allow it to dry and then sand it over to obscure the blemish.

Refinish your interior column(s) to match your décor. Brush on sand-infused paint to texturize the column for an organic, natural feel, employ a faux finishing kit to replicate the look of marble or granite -- or paint on a special effect emulating a mottled texture that’s reminiscent of wind-swept columns exposed to natural elements over time. Use additional amounts of plaster mortar to attach prefabricated embellishments and then add the finishing medium to the column so the decorations appear to have been part of the mold.

Construct a grand architectural statement by stacking small columns atop one another to fashion a one-of-a-kind, tall structure if you were unable to find a single mold that’s tall enough for your needs. Use thick plaster paste to bond the small columns together. For a cohesive finish, don’t refinish, decorate or embellish the column until all of the mini-pillars are in place.