Oak or Mahogany for external door?

Possom

Just wondered what opinions were on the strength and also the resistance to rot of an external door made from mahogany compared to oak?

Oak appears to be the more expensive.

Reece_

Are the doors you're looking at actually solid timber throughout? Most available through suppliers now will be a composite whereby it's a chipboard core, veneered and lipped all round with solid timber, they will still advertise these doors as "solid wood" as strictly speaking they are as they're not hollow. If it is these doors it will make very very little difference as to whether it's oak or mahogany.
If they are indeed completely hardwood construction then mahogany ( although there's several species marketed as mahogany) is denser and considered to have better rot resistance than oak, however oak is still a very good timber for external use and rot resistance is very good.

Possom

Reece_ wrote: »

Are the doors you're looking at actually solid timber throughout? Most available through suppliers now will be a composite whereby it's a chipboard core, veneered and lipped all round with solid timber, they will still advertise these doors as "solid wood" as strictly speaking they are as they're not hollow. If it is these doors it will make very very little difference as to whether it's oak or mahogany.

Thanks very much Reece_ for that tip; I'll make sure to check that.

Reece_ wrote: »

If they are indeed completely hardwood construction then mahogany ( although there's several species marketed as mahogany) is denser and considered to have better rot resistance than oak, however oak is still a very good timber for external use and rot resistance is very good.

That's good to know. Due to the more expensive price of the oak I'd just have assumed it was the reverse. Or perhaps this is one of the several species similar to mahogany.

Meranti is one type of hardwood I've seen advertised by a door manufacturer, so if you happen to know anything about this it would be interesting to hear.

leveller2911

Possom wrote: »

Just wondered what opinions were on the strength and also the resistance to rot of an external door made from mahogany compared to oak?

Oak appears to be the more expensive.

Oak can come in alsorts of species and quality. The better the quality the longer it will last.There are various qualities from Character grade which can have large knots which is not good for making doors through to Super Prime quality which has very few small pips (knots) if not clear of knots.

Typically , Exterior doors tend to be constructed from either European Oak or American White Oak. AWO is very hard , not as durable as Euro Oak and has less character than Euro Oak. The down side to using Oak for an Exterior door is that within a few months it will go black from the bottom rail upwards due to the tanic acid in the Oak leaching out. In time the door will go grey and you will lose that nice rich Oak colour. No one has yet invented a coating or finish that will stop the tanic acid from leaching out of the grain so if you accept the door will go grey then fin and in Oak there is no reason why it can last over 100 years. The only time Oak can rot early is if they use the sapwood (paler coloured part of the tree just under the bark) as this is not durable.

Hardwood wise I would look at species such as Sapele (member of the Mahogony family) Idigbo or Iroko. The one down side to Iroko is that it can warp and twist but its very durable. Don't consider Meranti, its very light in weight, damages easily and is not as durable as the others mentioned.

You could consider Douglas Fir (imo is the only softwood thats worth using and is classed as durable as Sapele and Idigbo) or Accoya which is a trade name for a softwood pine species called "Radiata" which has been impregnated with Acetic acid. They will warranty the timber for 60 years in the ground so its classed as durable as Oak.

Cost wise below is the most expensive at the top down to the cheapest at the bottom.

1: European Oak
2: Accoya and American White Oak (95% the costs of Euro Oak)
3: Iroko ( 50% the cost of Euro Oak)
4: Sapele (40% the cost of Euro Oak)
5: Idigbo and Douglas Fir (30% the cost of Euro Oak)



HTH......:D

Possom

Thanks very much leveller2911, this is very helpful indeed!

I had seen a door for sale which is the exact style I am looking for and it is made from Meranti.

So, your post has saved me a costly mistake! I could ask them to determine if they could possibly manufacture one from one of the better woods which you mention.

leveller2911

Possom wrote: »

Thanks very much leveller2911, this is very helpful indeed!

I had seen a door for sale which is the exact style I am looking for and it is made from Meranti.

So, your post has saved me a costly mistake! I could ask them to determine if they could possibly manufacture one from one of the better woods which you mention.

The reason they use Meranti is for two reasons. The first one is its cheaper than most durable hardwoods and secondly because its soft it machines easily so it doesn't blunt the machine tooling during manufacturing. Its purely down to costs.

TRADA (Timber research and Development Agency) classes Meranti as "slightly durable" whereas Sapele is Moderately durable, and softwood pines are slightly durable but this can be increased if they are impregnated with preservatives ,the down side is they are less stable than most hardwoods and tend twist,warp,expand and contract. Iroko is classed as durable as is Euro Oak . There are only 4 classes so although Sapele is moderately durable its still a good timber for exterior work.