The air valve is one-way and you can press the center to release air at any time. the back end of the valve unscrews so you can sandwich the fabric between the plastic housing. I basically cut a hole in the fabric the size of the internal hole and then threaded the back end of the valve back on. You could also put a sealant/glue to re-enforce.
Answered on 9/18/2012 by Anonymous
Yes this valve is pressure sealed by screwing parts together with a rubber like gasket to seal out air/water. Good luck? Let me know if you have other questions.