In 1913 an investigation was begun with the object of developing an all masonry barn which could be constructed at a reasonable cost and yet have the advantages of permanent and fire resistant construction. The studies which have been conducted pertain chiefly to the roof structure, with particular emphasis on the method of construction.

In addition to a number of design studies, models of roof sections were built to develop a method of roof construction. Strength tests were made on roof models to check the reliability of the designs. The information obtained served as the basis of the design and method of constructing an experimental barn, which was built at Iowa State College in 1926-27. Common overall dimensions and a desirable roof shape were established to make the roof forms usable for a number of barns; wind load assumptions were adapted from reliable wind pressure investigations to permit a more intelligent and efficient roof design.

The results of the design studies, construction and tests on models and roof sections, and the construction of the experimental barn, together with other related experiences, seem to warrant the following general conclusions:

1. The masonry arch is a very stable type of roof structure as shown by the tests on sections, which check closely the design calculations.

2. The construction of the roof is difficult and involves a large amount of labor because of: a. The use of heavy steel forms to carry a large part of the roof weight. b. The manipulation of the forms in erection, moving, dismantling and transporting. c. The handling and placing of roof materials.

3. The additional cost of the roof over a wood frame type construction is due. not so much to the cost of materials, as to the cost of the unproductive labor in handling the materials and in manipulation of the steel forms. The overhead cost of the forms becomes a large item in the first cost if they are used for only one or a few barns.

4. Experiments in the methods of making a roof watertight have not as yet indicated an entirely successful method. A heavy fibered asphalt has been found the best of the waterproof coatings which have been used. Leaks appear to be due to slight openings in the joints and to the development of fine cracks.

5. The construction of the roof should be directed by one . who is familiar with masonry construction.

6. A roof with a span of 34 ft. and a height of 20 ft. provides enough storage space for most conditions.