Page:A history of architecture on the comparative method for the student, craftsman, and amateur.djvu/351

 ENGLISH GOTHIC. 293 however, that this was the origin, and there is Httle more resemblance between a hammer-beam roof and a tie-beam roof than consists in their both being double framed, i.e., both having principals or trusses placed at regular intervals, as opposed to the trussed rafter type, which has no principal. Moreover, the tie- beam was used in all types of roof, even in conjunction with the hammer-beam itself, as at Outwell, where the intermediate principals are supplied with hammer-beams ; this is a late example, and was probably constructed after the hammer-beam type had attained perfection. Hammer-beams were not con- structed until the end of the fourteenth century, and were not in general use until the fifteenth century. Westminster Hall is the earliest recorded example, a.d. 1399 (No. 113 h). There are many varieties of this form of roof : — (a.) Those with hammer-beams, struts, collars and curved braces, as Little Welnetham Church, Suffolk. (/;.) Those in which the collar-beam is omitted and curved braces carried to the ridge, the apex being framed into a wedge-shaped strut, as at Trunch Church, Norfolk (No. 113 d). {c.) Those with collar- beams and no struts but curved braces, in which a shorter hammer- beam is used, as at Capel S. Mary, Suffolk, {d.) Those with no collars and no struts, curved braces only being used from ridge to hammer- beam, as at Palgrave Church, Suffolk. The arch- braced roof is the outcome of this latter form, {e.) Those with a main arched rib springing from wall-piece and reaching to a collar, forming a rigid chief support, as at Westminster (No. 113 h) and Eltham. Double hammer-beam roofs have two ranges of hammer- beams, as at S. Margaret, Ipswich, and Middle Temple Hall (No. 113 e), the object of the second range being to further stiffen the principals and convey the weight on to the first range and thence to the w^all. They usually occur when the pitch is flatter, but the effect is more complicated and less pleasing. These are the main divisions, but there are various minor modifications of the type. (4.) " Collar-braced Roofs " are a simplification of the hammer-beam form, and include arch-braced roofs, so called when the collar is omitted and the arched brace carried up to the ridge. This form is very like that constructed nearly a century earlier, as at Tunstead Church, but with the important difference that at Tunstead the braces are of the same thickness as and appear to form part of the principal rafters, whereas the collar- braced kind are not more than 4 inches thick, while the principals may be about 10 inches. Pulham Church, Norfolk (No. 113 c), is an example of this collar-braced form. Brinton Church is another example of the arch-braced type. The curved braces answer the double purpose of strengthening the principals