Rotting in Marine Plywood 1

[pba]

We are looking at a project where marine plywood has been used as flooring, with vinyl glued to the plywood. The subfloor is wet and the plywood appears to have a high water content.

I imagine that there is a strong possibility of rotting but have found no direct evidence of this. Is there anything used in the manufacture of marine grade plywood that would inhibit rotting?

By the way - The project is in England.

 

[SlideRuleEra]

In the US, marine plywood does not have any special properties to retard rotting.

To meet APA requirements, it is made from either douglas-fir or western larch, the interior plys are solid (no voids), and exterior glue is used. It is available with either MDO or HDO face. It is sometimes referred to as "Superior Exterior", rather than marine.

http://www.SlideRuleEra.net

 

[valleyboy]

I don't think marine ply has any rot-retardant material added during the manufacturing process - it is just made of more durable timber. If the timber will be used in a wet environment, then wet rot may be an issue - did you consider using treated marine ply?

I found the following data on the TRADA web site.

'Marine plywood (BS 1088)

Marine plywood to BS 1088 is manufactured using timbers having a durability rating of Class 3 (moderately durable) or better in accordance with BS EN 350-2. Exceptionally, low density species such as gaboon, with a durability rating of Class 4 (slightly durable) or better may also be used. In both cases, high quality veneers are used and must be bonded using either a phenolic resin or a melamine-formaldehyde (amino) resin to meet bonding Class 3 of BS EN 314. Marine plywood is available from UK, Israel, France, Singapore, Malaysia and other sources.

Marine plywood was developed for ship/boat building and has a very high performance under severe exposure conditions. It is also commonly used in construction applications where high performance is required or where the cost of replacement or consequences of failure warrant the additional cost. In the case of construction applications, the plywood must demonstrate compliance with the CPD, e.g. by complying with BS EN 13986.'

Registration is free and there are a lot of resources for ply and timber products on the web site.

http://www.trada.co.uk/

Regards

VB

 

[pba]

Thank you both.

You confirm my understanding. I think I'm safe in advising that this deck is at risk of rotting!

Valleyboy, thanks for the TRADA link, I have that information and the BS. We didn't design this floor - it's an existing kitchen floor which has failing vinyl and needs repair to comply with hygene requirements.

We have become involved through the Architect who suspected a structural problem unrelated to the floor...