plumbing prep

received the plumbing permit from the county yesterday - $100. i've been working out the details of supply pipe materials & layout, and DWV layout & fittings.

supply pipe will be pex, utilizing what's known as the 'home run' layout method. essentially, each fixture is fed by a dedicated line from a central manifold. this minimizes joints in the system - potential points of leaks, and points of pressure loss. fewer fittings allows a smaller diameter pipe, which reduces time & volume of water wasted waiting for hot water.

there are many options for stubbing out pex. i am utilizing some special bend fittings which allow the pex to run directly out of the wall, without any fittings inside the wall. stop valves attach directly to the pipe.. i'm also utilizing 3/8 lines throughout most of the system to minimize hot water wait times. cold lines will match to provide similar pressure drops to the hot water. the only 1/2 lines in my design are for the tub and sillcocks.

i was hoping to purchase the pex material from lowes, as they have a decent selection and a local source would be useful for any additional material needs i might have. some online anecdotes suggest trouble when mixing fittings and pipe from different manufacturers. unfortunately, lowes doesn't stock 3/8 coil pipe nor manifolds, so i must look elsewhere. also, a little digging uncovered the astm standard for crimp fittings on pex pipe - astm f876 & astm f877 & astm 1807. fittings & pipe meeting the standards should be physically compatible. so i'll be purchasing materials both online & locally.

i decided on using crimp ring connections for pex as these are commonly available and inexpensive. another connection system by wirsbo expands the pipe to fit around fittings, then the pipe retracts back to a tight fit within a few seconds. this is likely the fastest install method, and many people argue its the most dependable connection. however, the tools and materials are more expensive - and i've got a heavy cost limit now. i don't think the time saved by this tool on this job alone would justify the extra cost.

next on my agenda is to detail the dwv sufficiently to allow purchasing the PVC pipe & fittings i'll need. after that, i also have a few items on my agenda before actually beginning installation of pipework.