Paving Stones On an EPDM Roof

Has anyone here used paving stones on a flat roof? We have a job with a light weight concrete deck that we want to ballast with pavers. I am wondering if I need to cover the whole roof or if I can get away with spacing them out every 2 foot or so. The roof is one story about 30 x 42 feet with a 2 foot parapet wall around it. The owner would rather not have gravel for some reason and I need to figure this out soon. Thanks for any info here.>>>

Too often, I have seen "river rock" supposedly w/ sharp edges, that will inevitably pierce the membranes when traversed.>>>

Got the gravel down today and parapet copings. Will be putting pavers down on Monday. I'll use scrap rubber as a slip sheet. I may use a left over roll of sythetic underlayment that I have in the shop. (My new storage unit, yup, made the big time :laugh:)

VaaMike- the river rock is actually from a gravel pit. I believe it's glacial in origin, sand and gravel deposits. I think they reseed the gravel pit with pebbles and reharvest after a few years. :blink:

Mike, I looked into the Westile, but they were a bunch more. The pavers I got are from a landscape supply co. and they assured me that they would last. Hope they are right.>>>

Hi Gerry,

We have done a lot of it. Both as a ballast and as a deck surface. As a ballast, you simply need to distribute evenly to achieve a minimum of 10#/square foot average, but I like it a little heavier. The perimeter should be weighted more than the field. As a deck, of course they need to be tight.

Be sure to put a loose layer of membrane down as a slip sheet to protect the waterproofing layer from the concrete.

I would recommend WestTile pavers. They are 2x2 and heavy, but the concrete is of very good quality, very dense and holds up well. Cheaper pavers often disentigrate in our latitude.

Most people that want pavers only want them until they see the cost, then they do what your customer did and say "GIMMEGRAVEL"!>>>

Good choice, I'd take the river rock any day.>>>

Well, we decided to go with river rock except for a 10' x 20' section of pavers to be used as a patio on the roof so that the tenant can have his evening poker games in the summer. It's been an interesting job. This place should have been roofed a year ago judging by the amount of water under the roof. I think the deck is a s wet today as the day it was poured. >>>

I would be careful here, can the light weight concrete deck take this load? the 12x12 pavers mentioned by Jed are great in Tampa, I would not use them in colder climates they tend to break down thru freeze thaw cycles. What is the point of the pavers, protection? Foot traffic? You could always go with a lightweight gyp fastener with a proper pullout test and go fully adhered or mechanically attached system. If pavers are required I would go with a brushed 2x2 paver in a cold climate but at 40 lbs a paver you are adding 2.5 lbs a square foot of dead load.>>>

I recently finished up some service work on a roof of similar description in Boston. Despite it was a cold roof/ lightweight concrete, after installing the loose laid epdm.....a layer of 2 3/8 T&G styro was laid down and then pavers. Originally it has t&g with huge larger than golf ball size gravel, and access to epdm was expensive.>>>

We used 12 x 12 pavers on a TPO in Tampa a few yrs back, we spaced them out only an inch or so if I remember right.>>>