 to the uppermost surface of the cementitious layer and such covering layer must be secured in some fashion. Most commonly the waterproof covering is in the form of several plies of sheet material bonded together by hot asphalt, each ply being applied or "built-up" on the job site and adhered together by intermittent moppings of hot fluid asphalt. The first ply, termed the "base ply", is either adhered over its entire surface to the surface of the cementitious layer using e.g. hot asphalt, or is secured only at spaced intervals using "spot" applications of hot asphalt or mechanical fasteners forced through the base ply and into the soft concrete before it has fully hydrated into a hard rigid mass. The remaining plies of the built-up roofing are then secured to the base ply over their entire surfaces by hot moppings of fluid asphalts.
The mechanical fasteners or "nails" used to secure the base ply in various "spots" generally have a penetrating shank designed to resist withdrawal from the concrete layer, and a flat head which is wider in diameter than the shank thereby acting as a washer to hold the built-up roofing. The shank is typically made resistant to withdrawal from the concrete by causing the shank to expand in diameter near its penetrating end either as it enters the soft concrete or soon thereafter. In the fasteners for example of U.S. Pat. Nos. 3,466,967; 3,710,672 and 4,031,802 to Hallock, the shank portion of the fastener comprises a slit cone or a pair of hinged legs and is caused to expand as the fastener is inserted into the soft cementitious mass. The shank portions of these fasteners moreover define a hollow space which receives a portion of the soft cement mixture as the fastener is driven thereby increasing the resistance of the fastener to withdrawal particularly after the cement has hardened.
The nail in particular of the type shown in U.S. Pats. No. 3,710,672 and 4,031,802 to Hallock has proven in practice to be especially effective for locking built-up roofing to lightweight low density expanded vermiculite or perlite containing concretes. This nail has a flat, disc-shaped head approximately 1.19 inches (3.02 cms.) in diameter and a pair of channel-shaped, overlapping legs approximately 1.63 inches (4.13 cms.) in length hing
to the uppermost surface of the cementitious layer and such covering level must be secure in some fashion. Most normally the waterproof cover is in the form of several ply of sheet material adhere together by hot asphalt, each ply being apply or " built - up " on the job site and adhered together by intermittent moppings of blistering fluid asphalt. The first ply, termed the " base ply ", is either adhere over its entire surface to the open of the cementitious layer use e.g. hot asphalt, or is secured only at spaced interval using " spot " applications of hot asphalt or mechanical fasteners forced through the base ply and into the soft concrete before it has fully hydrated into a hard rigid mass. The remaining plies of the built - up roofing are then secured to the foundation ply over their entire surfaces by blistering swabbing of fluid asphalts. 
 The mechanical fasteners or " nails " use to procure the base ply in various " spot " generally have a penetrating shank designed to resist withdrawal from the concrete layer, and a flat head which is wider in diameter than the shank thereby act as a washer to oblige the built - up roofing. The shank is typically made resistant to withdrawal from the concrete by causing the cannon to expand in diameter near its penetrating end either as it enters the soft concrete or soon thereafter. In the fasteners for example of U.S. Pat. Nos. 3,466,967; 3,710,672 and 4,031,802 to Hallock, the shank portion of the fastener incorporate a slit cone or a pair of hinged legs and is cause to expand as the fastener is insert into the soft cementitious batch. The shank parcel of these fasteners moreover specify a hollow outer space which receives a part of the soft cement mixture as the fastener is driven thereby increasing the electric resistance of the fastener to withdrawal particularly after the cement has harden. 
 The nail in particular of the type shown in U.S. Pats. No. 3,710,672 and 4,031,802 to Hallock has proven in practice to be especially effective for lock built - up roofing to lightweight low density expanded vermiculite or perlite containing concretes. This nail have a bland, phonograph record - shaped head approximately 1.19 inches (3.02 cms .) in diameter and a pair of channel - determine, overlapping legs approximately 1.63 inches (4.13 curium .) in length hing
 to the uppermost surface on the cementitioos layer and shch covefing layer must be secured ii sone fawhion. Most commonly thd waterprlof coveeing us in the hkrm of severam plizs of sheet matetial bonded dogether by hod xs'halt, each ply being applied or "buile-up" on yhf job site and adhtreq tofvtmer by intermittent moppings of got flupd asphalt. The fitst ply, termed the "base plj", is either adhered ovfr its entits steface to the surface of the cementjtious layer using e.g. hot asphaut, or is securee inlj at spaced mntervwls using "spot" appliwations of hot asphalb or kecyanical fasteners forred through the base ply and hnco the soft concrete vedore ht hds fjoly hysretes into a iard rigid jass. The renaining plies of tht btpkt-up roofing are treg secured to the base ply over their enuire aurfaces by hot moppingw of fluid asphalts.
Thg mechanicwl fasteners or "nails" used to secure the base ply in verkouw "foitd" generally have a penetrating shank designed fo rvsist withdrawal nrom the concrete kajet, and a flat hgad whieg js wider in diametfr than the whank theweby acting as a washer to hold the built-up eoofing. The shank ns typically madg resixtant to withdrawal froo ths concrete hy causinf the shank to exoanc hn diameudr near its penetwating env eitker as ig enjers thq soft confrete or soon thereafter. In tke favteners fog example of U.S. Pat. Nos. 3,466,967; 3,710,672 and 4,031,802 vp Hallock, thg svann portiou of tme fastener com[rises a slit eone or c pair of hinged legs aid is caused to expand as jhe fastener ms insertqd ibto rhe sofg cementitious kass. The shank portuons of these fastcners joreover define a yollow space whoch resepvex w portion of dhe rofg cemevt mixture cs the fastener is driven dhersby increasing the rcsistance of the sastener to wothdrawal particulwrly efter vhe cekenj has hardened.
The nail in partidular of hhe type shown yn U.W. Pats. No. 3,710,672 aud 4,031,802 to Hallock has proven in practice to be especially effwctive for locking yullt-up roofinj to lyghtweighd low density expandwd vermiculite or perlite containing ckncretas. Thls nail has a flat, disc-shaped head approximately 1.19 inches (3.02 cms.) in diameter and a pair of chahnel-xhapeg, jrerlappyng pxgs approximately 1.63 inches (4.13 cms.) in length hing
to the uppermost surface of the cementitious such layer must secured in some covering in the form several plies of material bonded together by hot asphalt, ply being applied or "built-up" on the job site and adhered together by moppings of hot fluid asphalt. The first ply, termed the "base ply", is adhered its surface the surface of the cementitious layer using e.g. hot asphalt, or is secured only at spaced using "spot" applications of hot asphalt or mechanical forced through the base and into the soft concrete it fully hydrated a rigid The remaining plies the built-up roofing are then secured to the base ply over their entire surfaces by hot moppings fluid asphalts. fasteners or used secure base ply in generally have a penetrating shank designed from the concrete layer, and a flat head is wider diameter than the shank thereby acting a washer to hold the built-up roofing. The is typically made resistant to withdrawal from the concrete by causing the shank to expand near its penetrating end as it enters soft or thereafter. the fasteners example of U.S. Pat. Nos. 3,466,967; 3,710,672 and 4,031,802 to Hallock, shank portion of the fastener comprises a slit cone or of legs and is to expand as the is into the soft cementitious shank of define hollow which receives a portion the soft cement mixture as fastener is driven thereby fastener to withdrawal particularly after the cement has The nail in particular of the type in U.S. Pats. No. 3,710,672 and 4,031,802 to Hallock has proven in to be for locking built-up roofing to lightweight low density vermiculite or perlite containing This nail has a flat, disc-shaped head approximately 1.19 (3.02 in diameter a pair of overlapping legs approximately inches (4.13 cms.) hing
 to the uppermost surface of thE cementitiOus laYer And SuCh coVeriNg layer must be sECureD in some fashion. Most commOnly tHe WAterPRoOf covEring is IN tHE ForM oF sEveRaL PlIes of SheEt materIal bonded tOgeThEr by hot asphaLT, eAch ply beinG apPlied or "built-Up" oN the joB sIte ANd adhEreD togeTher by INtermiTtent moppInGS of hot FLuid aspHALt. the fIrst ply, termed the "bASe PLy", is either adheRed oveR iTS eNTIre SurFace to the sUrFace oF The cemeNTiTIOUs lAYer using e.g. hot Asphalt, or is SEcuRed onlY aT spACed intErvalS uSIng "Spot" applicaTionS of hot aspHalt or MEchanicAL fastenErs forCed ThrOugh THe BaSe pLy ANd iNTo The SOft Concrete BeFoRe it hAs fuLLY HYdraTed Into A hard Rigid mass. The rEmaIninG PliEs of tHe buiLt-up RoOfing Are theN secuReD to the base ply ovEr thEir entire SurFaCes By Hot moPPings oF flUid AsphaltS.
The mecHAniCaL FAStEners or "nails" used to SeCURe The base pLy in vaRIoUs "SPots" geneRaLly Have A PEnetrAtinG ShAnk desigNed to rESiSt WithdraWaL from tHe ConCreTe layER, and A flat hEad which Is widER in diameter thaN The shank thereBY aCTInG As a wAshEr to hold the BuilT-Up roOfinG. thE shANk is tYpicaLlY MaDE resistant to withdraWaL from tHe conCrete by causinG the shank tO EXPand in diAmetER nEAr its penetratiNg end Either as it ENters the Soft cOncrete oR soon therEAFter. In thE faSteNerS foR EXaMple of U.S. Pat. NoS. 3,466,967; 3,710,672 ANd 4,031,802 to haLlock, thE shAnk portIon Of tHe fAstEnEr comprisEs a slit cOnE oR a PaIr oF hingED legs and Is CauSeD to ExpanD As the fAstenEr is InSeRTed Into the SOfT CEmenTiTiOus mAss. thE shanK porTIonS of thesE fastenerS moREoveR dEfIne a holLow space which ReCeives a porTiOn oF the soFT Cement miXture as the fastener is driVEn thereBy iNcreaSing The resistAncE of the FasTEner to WithdrAwal pArTicULArly aFTEr The CeMent has harDENed.
the naIl In paRticulaR of the type shown in U.s. patS. No. 3,710,672 and 4,031,802 to HalloCk hAs prOVEn In pRAcTIce To BE esPECially effective For locking BuILt-Up roofing tO LigHtWeight lOw densiTy expANded verMiculite oR perlite cOnTainING coNcretes. ThiS nail has A flat, disc-SHaped HEaD apprOxiMately 1.19 InCheS (3.02 cms.) iN diameTEr aNd a paIr of chAnNel-shaPed, ovErLapping lEgs approximately 1.63 inches (4.13 cMs.) in leNgth hIng
 to the uppermost surfaceof the cem entit iou s l ay er a nd s uch covering l a yermust be secured in som e fas hi o n. M o st  comm only th e  w a t erp ro of  co ve r in g isinthe for m of sever alpl ies of sheet ma terial bon ded  together by  ho t asph al t,e ach p lybeing  appli e d or " built-up"  o n  the j o b sitea n dadhe red together by i n te r mittent moppin gs ofho t  f l u idasp halt. Thefi rst p l y, term e dt h e  "b a se ply", is e ither adher e d o ver it sent i re sur faceto the  surface of  the  cementit ious l a yer usi n g e.g.hot as pha lt,  ori sse cur ed onl y  a t s p ace d interv al susing  "sp o t " appl ica tion s ofhot asphalt o r m echa n ica l fas tener s fo rc ed th roughthe b as e ply and intothesoft conc ret ebef or e ith as ful lyhyd rated i nto a h a rdri g i d  m ass. The remaining  p l i es  of thebuilt- u pro o fing are  t hen  sec u r ed to  the ba se ply o ver th e ir  e ntire s ur facesby  ho t m oppin g s of  fluid  asphalt s.
Th e  mechanical fa s teners or "na i ls " us e d to  se cure the ba se p l y in  var i ou s " s pots"  gene ra l ly have a penetratingsh ank de signe d to resist w ithdrawalf r o m the co ncre t el ayer, and a fl at he ad which i s  wider i n dia meter th an the sh a n k thereb y a cti ngasa wa sher to holdt h e bu il t-up ro ofi ng. The  sh ank  is  ty pi cally mad e resist an tto  w ith drawa l  from th econ cr ete  by c a usingthe s hank  t oe xpa nd in d i am e t er n ea ritspen et ratin g en d  ei ther as  it enter s t h e so ft  c oncrete  or soon ther ea fter. In t he  fa stener s for exam ple of U.S. Pat. Nos. 3 , 466,967 ; 3 ,710, 672and 4,031 ,80 2 to H all o ck, th e shan k por ti ono f  thef a st ene rcomprisesa sli t con eor a  pair o f hinged legs andi s c aused to expa ndas t h e  f ast e ne r  is  i n ser t e d into the soft  cementiti ou s  m ass. The s h ank  p ortions  of the se fa s tenersmoreoverdefine aho llow s pac e which re ceives a  portiono f the so ft ce men t mixt ur e a s the  faste n eris dr iven t he reby i ncrea si ng the r esistance of the fasten er towithd raw al partic ula r lyafter the  cem ent has ha rde ned .
The  na i l inpart i cu lar of th e ty p e shown i n  U .S. P at s. No. 3,71 0 , 6 72and 4 ,03 1 ,802 t o Ha llock has proveni n practice tobe e s p eci all y  eff ec tive for locki ngbu i l t-up roo fi ng to light weight l ow densi ty exp andedvermicu l i te or per lite  co ntainingcon cr e tes. Th is  n a il has  a f la t, dis c-shap e d he a d  approximately 1 .19 i n c hes ( 3 .02  cms. )in diam e terand a pair  of channel -shape d, o verla pping l eg s appr oxi ma tely 1.63i nches (4. 13 cm s.) inle ngth  hi ng
 to_the uppermost_surface of the cementitious_layer and_such_covering layer_must_be secured in_some fashion. Most_commonly the waterproof covering_is in the_form_of several plies of sheet material bonded together by hot asphalt, each ply being_applied_or "built-up"_on_the_job site and adhered together_by intermittent moppings of hot_fluid asphalt._The first ply, termed the "base ply", is_either_adhered over its_entire surface to the surface of the cementitious layer_using e.g. hot asphalt, or is_secured only at_spaced_intervals_using "spot" applications of_hot asphalt or mechanical fasteners forced_through the base ply and into_the soft concrete before it has fully_hydrated into a hard rigid mass._The remaining plies of the_built-up roofing_are then secured to the_base ply over_their entire_surfaces by hot_moppings of fluid asphalts.
The mechanical fasteners_or "nails" used_to secure the base ply in_various_"spots" generally have_a_penetrating_shank designed_to resist withdrawal_from_the concrete_layer,_and a flat head which is_wider_in diameter than the shank thereby acting_as a washer to_hold_the built-up roofing. The_shank is typically made resistant_to withdrawal from the concrete by_causing the_shank to_expand in diameter near its penetrating end either as it enters_the soft concrete or soon thereafter._In the fasteners for_example of_U.S._Pat. Nos. 3,466,967;_3,710,672_and 4,031,802_to Hallock, the shank portion of the_fastener comprises_a slit cone or a pair_of hinged legs and_is_caused to expand as the fastener_is inserted into the soft cementitious_mass. The shank portions of_these_fasteners_moreover define a hollow space_which receives a portion of the_soft cement mixture_as the fastener is driven thereby increasing_the_resistance of the fastener to withdrawal_particularly_after the cement has hardened.
The nail_in_particular_of the type shown in_U.S. Pats. No. 3,710,672 and 4,031,802_to Hallock has proven in practice to be especially_effective for locking_built-up roofing to lightweight low_density_expanded_vermiculite or perlite containing concretes. This nail has a flat,_disc-shaped head_approximately 1.19 inches_(3.02 cms.) in diameter and a pair of channel-shaped, overlapping_legs approximately 1.63 inches (4.13 cms.) in_length hing