If I'm going to let my decking material just naturally weather to a silver tone is there any reason to not to just go with Cumaru boards as they are almost as dense as IPE and are quite a bit less expensive? I suspect Cumaru is similar to IPE as far as installation. Anyone have experience with Cumaru?

A quick sanding w/ 60 grit on a RO takes away all the little Ipe splinters. Drilling the pilot holes into the PT frame will cause the boards to come loose. Using screws that are longer than necessary amplifies the effect of the head popping up as the joist shrinks. A 3.5" long screw embedded 3" into a 2x8 joist will pop out nearly twice as much as 2" long one with 1.5" embedment in the same joist. Use the shortest screw that will do the job, and do not drill the pilot hole into the joist. Use adhesive to hold the decking to the joist. Think of the screw as a clamp. After one day the adhesive is cured and the clamp can be loosened without losing the bond. Wood decks expand and shrink each season, a lot the first season and a bit less each year as the wood weathers. So the "clamp" gets constantly loosened and tightened a little bit. Retightening the screws one time after installation, or right before plugging may be a smart practice especially in dry climates. However I would not recommend continually retightening the screws manually. You will eventually strip or break the screws. if you overtighten them during the dry season, some may snap during the next wet season. Pressure treating reduces strength. Doug Fir (the wood available on the west coast) is not quite as strong as Southern Yellow Pine. PT Doug Fir 2x joists should be No. 1 structural grade. That is special order material you will not find on the shelf. It is easy to get but you have to pre-order a few days ahead. The 4x and up PT material is generally No. 1 but ask to make sure.

Anchor seal is a must in my book to keep the ends form checking. I would not glue down the boards as this will not allow the proper expansion and contraction of the wood from my perspective. Grace Vycor on the joists or anything for that matter would not be a good idea either in my mind.

Hello my name is Scott Morris and I have previously posted comments on here before specifically about Mangaris (Red Balau) and Ipe decking. I have spoken to and met with several people in the Southern California area. I have worked for BlueLinx (a wholesale building materials distributor of Mangaris and other decking products) for 8 years as well as 20 years experience on the retail lumber side. As in my earlier post, the biggest issue with any hardwood decking is in the installation. I have included the complete installation guidelines for you to read. The biggest issues always seem to be, #1 Improper or lack air ventilation under the deck . #2 Gapping in between each board. Kiln Dried product will require 1/4" gapping on a 1x6 board while products like Ipe that are only Air Dried will generally require only 1/8" because they will shrink up over time and become 1/4". #3 Fasteners used on the decking. Hidden fasteners are usually not recommended for hardwood decking. Screwing the board down through the face has about 4x the holding power of a hidden fastener. You should either use a stainless steel screw, a plug system with stainless steel screws or a system like the Kreg Deck Jig that screws in at an angle on the side / edge of the board. #4 Is oiling / sealing the product. You either need to oil all 4 sides prior to installation with a good penetrating oil, or, leave all 4 sides raw and allow the board to weather to a natural silver gray color. This is popular in larger commercial applications like the LA Zoo, Disneyland, boardwalks near the beach and several larger outdoor shopping centers about the LA area. I have recently opened my own wholesale direct to the public distribution for hardwood decking products. I offer Kayu Batu (Red Balau, same as Mangaris Red) which is a Class A flame spread rated hardwood decking with a 25 year warranty and Siap (pre-finished) hardwood decking exclusively in Southern California. I also have deck tiles available in 20"x20" and 40"x40" sizes, as well as 6' & 7' "shorts" than can be used for fencing with an additional savings of up to 30% compared to the longer length materials. All my products are at very competitive pricing, usually 20-30% less than what you will find at the large retail lumber yards. This is because I buy direct and I'm the exclusive distributor of Kayu International decking products in Southern California. You can call or email me to check pricing on all my products, 818-456-9777 or hardwooddeckingdeals@yahoo.com . I'm in the Los Angeles area in Pacoima. Will call or delivery is available to all of Southern California. Here is a link that might be useful: Kayu International