Logs don't dry very well the center will stay wet and rot. Commercialy wood is cut and "stickered" slts between the layers of boards to allow air circulation. I have seen do it yourself kilns for a large quantity, of lumber some type of roof to keep of rain plastic sheeting or glazing on the south side. You will also need air movement. Fans with humidistats and thermostats could be installed to draw air through the enclosure. I have cut 3in. walnut and dried it in the rafters of my garage, allow 1yr. per inch of thickness, some say this is the best for the wood. At the old military fort in Fort Scott KS. the front pillars of the officers quarters are about 30 ft. tall and 36 in. at the base they were cut in the woods, then a 3in. hole was bored through the center, then they were turned on a lathe, no cracks in them and they are 100 yrs. old. The stuff that I cut for knife handles I cut oversize slabs and blocks"to allow for shrinkage and warpage" 1/2 to 3/4 slabs 16 to 24 in. long and 1 3/4 block the same length and just put them on the shelf in my shop, and get them out next year. Have fun, What kind of wood?