Im with TROPHMICK and the FABSIL
 

FABSIL is wicked stuff! NOT JUST FOR TENTS!!!!

It waterproofs riding gear too! but bear in mind it is called "FAB-SIL" because it gets its name from FABulous SILicone.......which is slipperier than a greased pig!

so no waterproofing the palms of your gloves! its dangerous..:oops2: ( DONT ask me how i know :eek3:)

The bad news with tents is that applying a DWR (durable water repellant-the durable part for nikwax and fabsil doesn't really apply. The most "durable" water repellant treatment is by grangers-but (like your waterproof & breathable jacket) requires light ironing/low dryer to set the water repellant. Since you cann't do this to a tent -if the pu coating on the base is gone a tarp footprint is the only work around. (The angle of the flysheet and DWR will only slow down the water coming through.) Have a look at Gelert.co.uk if in the Uk they do some really good and cheap solo/2 person tents. (£25 for a 1.5kg solo tent!)

An alternative -if you have a sewing machine around- is to replicate the flysheet. Ray Jardine's website-http://www.rayjardine.com/ is a great site for making your own gear walking or biking. Also quite inspirational for those bitten by the adventure travel bug!

up hill battle
 

Unfortunatly making a ten year old tent water proof would be like getting butter up a porcupine's a*#e with a red hot neddle....

Go to any outdoor store and they'll have a few "brews" to put on it but it won't work very well or at all. Like some of the others have suggested sling a tarp over the top woulb be your best not-buying-another-tent option

Problem with synthetic fabrics is the very limited life regardless of the use... aound 7- 10 years. After this they start breaking down and also delaminting