Thread: A17 and F17 Kild dried HD for decking questions..

Originally Posted by johnoadams

Hi, i am new here but have often found myself looking at anwsers to my questions through Google serches.

Anyway.

I have an idea to use kiln dried (well i think it is) F17 Hardwood as Decking in a more Boardwalk fashion than the smaller deck widths and thickness of tradtional outoor decking like merbau.

The pricing is reasonable and evenmore so as it would not require Joists, only bearers to create the deck with say 140width x 45thick I can also use 120, 200, or 240!!

ANd i was going to attach it with Bugle screws...

I think it should look really chunky and nice.

Now i have heard that some one has done this before...but never have seen it. (anyone know of anyone? Photos?)

My questions are these...

What timber is F17 hardwood? Which trees are they from?

The F17 will stay straight and should be good to work with and when new ,looks great....but tends to Craze and go grey.... Would sanding and then oiling/sealing F17 be enough to help kep the naturual color of the timber and prevent crazing ??

The Crazing and greying are the 2 main concerns for me...Anythoughts on this?

A17 is like F17 but is Laminated....not an LVL...but has 2 pieces ie: 2 x 90mm wide to make 180mm and laminated to gether.... i was considering this stuff as it isstronger and laminated timber has an interesting look.

F Ratings.
F17 is a structural rating for timber - any timber.
The higher the F number, the stronger it is.
The F rating number is the amount of mega pascals required to form a 1% defection on a piece of timber 100x100 mm end section over a 1 metre span.
for a decking application, not only is structural integrity an issue, appearance is also a requirement.
NB> F rated timbers can look ugly.

Re- Graying.
Graying is caused by UV rays. Timber will tend to go silvery if left externally.
An external oil / stain will help eliminate this.

F17 kd is generaly vic ash or pine which are not the best timbers for external use for this type of deck you would be better off useing f17 GOS hardwood will shrink over time but will last a lot longer in the long run. GOS (Green off saw)

Originally Posted by PJ's

F17 kd is generaly vic ash or pine which are not the best timbers for external use for this type of deck you would be better off useing f17 GOS hardwood will shrink over time but will last a lot longer in the long run. GOS (Green off saw)

I'd like to know which pinus species goes F17 - Most pine sold these days is graded under MPG rules which is slightly different to F ratings - MPG10 & MPG15 for example.
Back to the issue at hand - Make sure the species is Duarability # 2 or BTR as per AS5604 and is free of sapwood (no sapwood is naturally durable).
Expect up to 10% shrinkage tangentially in some species of hardwood from Green to seasoned.