extraneous adhesive chemicals the sheet is simply cut to size the release sheet peeled away and the membrane positioned on the roof for immediate installation and instant bonding of membrane to the substrate while heat sealing any seams in the membrane structure the present improved single ply membrane exhibits superior puncture resistance of more than 250 lbf pounds force a tear strength of 124 u00d7 140 lbf or more and a peel strength greater than 45 lbs in addition the membrane has good chemical resistance while retaining a degree of flexibility at low and freezing temperatures further the pressure adhesive coating allows the membrane to conform to substrate irregularities and various roof areas such as roof hips and valleys having generally described the invention reference is had to the following examples which illustrate preferred embodiments and comparisons with current single ply membranes however these examples are not to be construed as limiting to the scope of the invention as defined by the appended claims equal parts of polyisobutylene of average molecular weight 100 000 polybutene of average molecular weight about 1 000 and thermoplastic styrene butadiene styrene polymer containing 30 wt butyl rubber are extruded into a mixing kettle and stirred at 220 u00b0 c for 0 5 hour to provide a spreadable pressure sensitive adhesive the adhesive is coated on the undersurface of a single ply polyvinyl chloride membrane in a thickness of about 50 mils to provide a single ply roof deck covering having resistance to wind lift without the need for mechanical fastening the above procedure is repeated except that the single ply membrane is fortified with a glass mat scrim embedded in the membrane the resulting product exhibits good resistance to wind lift when applied to a.