Thank you for sending images of the rosewood door. It seems to be in a severely exposed location. The black markings appear to be "iron stain", ie. a reaction between the timber and metal fixings, in the presence of moisture, as described in this data sheet: https://www.fpl.fs.fed.us/documnts/finlines/finishline_mknaebe_2013_006.pdf. It's not immediately clear which metal component is causing the problem. We wouldn't expect stainless steel to cause iron staining but perhaps the lock is the source as it shows signs of corrosion.
Iron stain Question
I am hoping you could possibly shed some light on this issue we are dealing with.
This is apparently the second time this door has discoloured the way it has.
The handle that is fitted is marine grade 316 Stainless Steel. The escutcheon below is not.
There is also a plastic buffer between the handle leg and the door itself.
The inside of the door has no markings.
We are trying to find a solution so that this does not happen again. Would the stainless steel react with the rosewood?
I could send some pictures showing you the discolouring/Bleeding
Question
I am building a low level deck using single span F7 140x 45 TP joists. What is the maximum span I can achieve?
The allowable span depends on the spacing. If the joists are spaced at 450mm centres the span is 2600mm. Spaced at 600mm centres the span would be 2200mm. For more information refer to data published by Timber Queensland, available here: https://qbis.com.au/wp-content/uploads/2015/08/Timber-Queensland-booklet-balustrades-and-durability1.pdf, or our Technical Design Guide no. 21 which can be downloaded here: https://www.woodsolutions.com.au/publications.
Decks close to ground Question
We intend cladding the front of our domestic project with timber - 6.65 m high.
Can you please advise the most economical timber to use and profiles?
Vertical cladding would not be available in 6.65m lengths and would not be practical from a handling point of view. Your cladding could be fixed vertically if staggered joints were acceptable, otherwise we suggest horizontally fixed cladding in a lapped weatherboard style. Western red cedar has good weathering properties and takes an oil or stain finish well. However, you also need to consider the practicality of maintaining cladding that is 6.65m above ground. Perhaps you intend to let it weather to a driftwood grey colour without a finish. Again, western red cedar is dimensionally stable under weather exposure. You could also consider a kiln-dried hardwood product. Our Technical Design Guide no. 13 titled Finishing Timber Externally deals with some of the issues associated with naural weathering. It can be downloaded here - https://www.woodsolutions.com.au/publications.
Cladding
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