John asks: My local lumberyard stocks mahogany decking at a good price. How durable is this compared to other hardwoods? How would you recommend finishing?
Steve Bliss, of BuildingAdvisor.com, responds: Most wood decking sold in the U.S. as “mahogany” is actually dark red meranti or, in some cases, red balau. Meranti and balau are in the same family as lauan, also called Philippine mahogany.
Think of meranti as hardwood lite. It is popular because of its low cost, attractive color, and easy workability compared to ipe and other super-dense tropical hardwoods. However, don’t expect it to last as long as ipe or similar hardwoods.
Because of its appearance and marketing, Meranti is often confused with “real mahongany”, also called Honduran mahogany, South American mahogany, or True Mahogany. This is a different species with much better resistance against insects and decay. Most now comes from plantations in Peru or Central America. It is rarely sold as decking.
Meranti has the reddish appearance of a tropical hardwood, but its durability is more similar to softwoods. It has moderate resistance to decay and insects, similar to cedar and redwood, but is not much harder than yellow pine. It rates about 900 on the Janka scale, which measures wood hardness, compared to over 3,300 for ipe.
On the other hand, meranti is prone to split at end cuts if the end grain is not well-sealed. It is also more prone to general checking and cracking then denser hardwoods.
If you use meranti, make sure you seal the cut ends as soon as possible and get a good penetrating oil finish on all sides before installation – and before it has had a chance to weather and possibly start to crack.
As with any wood decking, maintenance and refinishing are important for longevity and appearance. If you refinish with a good penetrating oil whenever it starts to absorb water (water no longer beads on the surface), you can get a decent service life and attractive hardwood appearance at a budget price.
Read More on: Hardwood Decking Deck Finishes
Stanlee says
Is Meranti A Good Choice For Bearchfront Deck
I have a large beach deck project(over 700 sq feet) and was told by my local lumber that Dark Red Meranti/Philippine mahogany is a good cost-friendly option. Being on the waterfront, and exposed to sea-water especially during high tides and storm surges, I worry about its durability. Is it a good choice for this type of project where it’s exposed to sea water occasionally?
buildingadvisor says
Red Maranti is another name for Philippine Mahogany or Lauan, the wood commonly used for the skin of hollow-core interior doors in the 1960s and 1970s.
Meranti is considered moderately durable to against wood decay and insects, roughly equivalent to cedar decking.
I wouldn’t recommend it for exposure to saltwater, which is a tough environment for wood. I’d recommend either pressure-treated wood rated as “marine grade” or choose a dense, durable hardwood such as Ipe or teak, both of which have a proven track record in marine environments.
Another option to explore would be the premium plastic and composite products rated for direct water contact. Expanded PVC is the most likely candidate as it contains no wood content to absorb water. Another option to consider is a composite product marketed for use around pools, such as MoistureShield.
With any plastic or composite materials, however, I strongly suggest you get documentation that the product manufacturers stating that the material can tolerate the level saltwater exposure that you anticipate and make sure their warranties cover that application.
Janet says
How To Clean & Finish Meranti Decking
I have a red meranti deck. I need to treat it to protect it. What do you recommend for prep. Pressure washing then oiling? Sanding then oiling? It has some mildew/dirt on the outdoor deck. The deck on the covered porch is a lot cleaner looking. Tung oil or another product? How many coats?
buildingadvisor says
Red Meranti is also sold as “mahogany” decking. It will perform well if maintained properly so you are wise to clean and finish the decking.
Pressure washing is an option, but is usually overkill and can damage a deck surface if you’re not careful. Commercial deck cleaners work well or you can mix your own (see Cleaning Details). It’s easy to apply the cleaner with a low-pressure garden sprayer and scrub, if necessary, with a stiff brush you can buy at any hardware store. Then rinse well and allow several days to dry, depending on the weather and sun exposure.
If the wood surface is rough and uneven after washing, you can sand the deck, but this usually isn’t necessary. Pressure washing can raise the grain with some woods, which would require sanding to provide a smooth surface.
As for the finish, you can read about hardwood deck finishes here (scroll down to Finishing Hardwood Decks). If you can find it in your area, I would use a penetrating oil stain formulated for hardwood. Some states don’t allow these and you need to use a low-VOC formulation. You can identify these as they use water for clean-up.
Avoid regular Tung oil or other oil finishes not specifically made for exterior decks as these are often too thick to absorb well and will support the growth of mildew.
If you want to maintain the reddish color as long as possible, use a lightly pigmented stain. The pigment will also help block the UV light, which is primarily what weathers the decking surface and turns it gray.
One water-based product that gets pretty good reviews is Cabot’s Australian Timber Oil – Series 19400.
ly the decking carefully to one or two boards at a time lengthwise, always maintaining a wet edge. Otherwise you may get lap marks or splotchy areas on adjacent decking boards. You can use a strip of thin plywood or a “paint guard” available at paint stores to keep the wet finish off adjacent boards.
Hardwood deck finish is thin, so it soaks into the dense wood. This also makes it easy to apply with a brush or wool applicator pad. Just brush it one, wait 10-15 seconds, then wipe off any excess with an absorbent rag.
It sounds like this wood was never finished, so it will probably take two coats – best to follow the manufacturer’s instructions.
You’ll know when it’s time to refinish when the decking readily absorbs decking stain or water. This might be yearly on the exposed portion of the deck but less frequently on the covered porch section.
Read more about Hardwood Decking