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Check existing rafters under new loading condition. Ignore the stiffness of the new 2x4 overframing. <br />Original specs call out Construction grade lumber, 2x10 does not come in that grade, therefore, <br />assume #2. <br />Material weights (assumed): <br />w2x10 =2.8 existing 2x10 @ 16" oc (psf) <br />wins 1.0 existing 2" fiberglass bat insulation (psf) <br />w plyl :=1.6 existing plywood sheathing (psf) <br />wbit =3.0 existing built-up roofing (psf) <br />w 2x4 :=1.5 new 2x4 overframing @ 16" oc (psf! <br />wp1y2 1.6 new plywood sheathing (psf) <br />w tch = 3.0 new torch -down roofing (psf) <br />wsno := 25 snow load (psf) <br />Member properties: <br />F b <br />= 1450 <br />F cn <br />= 625 <br />F v <br />= 95 <br />E'=1700000 <br />1 : = 98.93 <br />S :=21.39 <br />A :=13.875 <br />wtot:=w2x10+ wins *wplyl+wblt+w2x4+wply2+wtch*wsno <br />M:=wtot-Span'.1.5 fb:=S fb=1120 F'b:=Fb•CD <br />Fa,n <br />fv:=3•wtot' <br />2 <br />fv=43 <br />Fv:=FvCD Fv=109 <br />2A <br />5 w tot span <br />A tot <br />= 12 <br />A tot = 0.863 <br />span <br />an = 279 <br />tot <br />384.E.1 <br />w sno 4 <br />All. <br />5. 12 .sP� <br />_ <br />All=0.546 <br />an s <br />P —442 <br />384•E•1 <br />Ail <br />Span : = 20.104 <br />span :=12•Span <br />C D := 1.15 <br />w tot = 39.5 <br />Fb=1668 <br />Summary: Moment and shear check out O.K. The deflection check shows the system to be a <br />little soft but within code allowables (span/240). <br />I <br />Terry Metzker <br />16634 Juanita Dr NE Apt #01 F <br />Bothell, WA 98011 <br />CITY OF <br />AP RE <br />ED <br />By �ILDIN FO <br />1�2 <br />