I have a deck on the house that is currently nominal 2x4 of various species. (the previous owners had no taste). I want to replace the surface with Ipe wood. It comes as nominal 5/4 x 6 which is a better look IMO. The problem is how to make up for the smaller dimension?

  • Seriously, is ripping a bunch of 1/2 inch strips the professional way to go?
  • Would you paint the strips to keep moisture out?
  • I suppose I could use some of the PT that we pull up to make this shim, right?

A few edits to address the questions in the comments.

  • Yes i want the good wood called Ipe.
  • no the concern is not the stability of the floor, the joists are 24" or less
  • the concern is how it looks / behaves under the threshold of the slider doors and where the siding meets the deck.
  • yes I have been formatting the paragraph to look / read better, but it just keeps clumping it all together. uurgh...

A couple things the past few days....

2x Ipe is cost prohibitive, double the cost of the 5/4 Ipe. However Ipe is the way to go. Therefore we're thinking of putting a 1/2 inch shim on joists or putting a 'sister' joist that is 1/2 inch proud. We need the decking level to be the same after the thinner board. If there were a gap or even a filler bit under the doors and siding it would look like a mistake. There are 12 doors that meet the decking.

One pro suggested rubber flashing to help hold the 1/2" shim in place and bonus shed the water. Explain again why you wouldn't do this? How else to support doors?enter image description here

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    I'm not sure I follow your question - a quick sketch might help. Are you saying the current decking is 2x4 (laid on the 4" side, I presume), and that you're replacing it with the 5/4x6? Are you concerned about the difference in wood thickness between the 1.75" thick 2x4 and the 1.25" thick Ipe? If so, there's no concern at all - 5/4" lumber is quite sufficient for decking. The only issue might be the step distance from the deck into the house. Unless that distance is already at the max for comfort/code, the additional 1/2" step may take a day to get used to... – FreeMan May 22 at 13:06
  • ... but is otherwise not an issue at all. If I've totally misunderstood your question, please edit to provide more detail. (Also, some formatting instead of a single block of text would help readability.) – FreeMan May 22 at 13:07
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    Yes, why is this a concern? The only issue should really be at your door threshold, and there you can use a shim if it needs support. – isherwood May 22 at 13:11
  • A photo would be helpful, without any knowledge of your deck it would not be of much value. Your joists are 24” or less for 5/4 , are you using clips? @freeman T&G high density boards. – Ed Beal May 22 at 13:15
  • @EdBeal sorry, I'm not sure I understand your reference to me... "Ipe" is a species of (expensive) wood often used in decking, is "IPE" something different and that's what you're referring to? – FreeMan May 22 at 13:20

I would stay with 2 X lumber instead of 5/4 "decking". that will solve your dimension problem . Regular 2 X lumber is twice as strong, twice as stiff and lasts much longer, compared to 5/4 decking. My deck is 2 X 6 , 25 years old and I have made a few repairs. The community pool has some 5/4 decking ,it has been replaced twice in that same time and does not look so good right now. More objectively ,the strength is proportional to the cube of the thickness; that cube is 3.38 for 2 X lumber and for 5/4 the cube is 1.95, so not quite 2 : 1 difference. Update- I went to the pool today ,5/ 23, a new deck had been put on during the winter ,so 3 decks in about 25 years. But, this time someone got smart and put in 2 X lumber instead of 5/4.

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  • Deleted earlier comment where I said ipe was stiffer than softwoods... I went to the sagulator and discovered that 5/4 ipe is slightly more sag-y than 2x pine or redwood. – Aloysius Defenestrate May 22 at 22:38
  • "Regular 2 X lumber is twice as strong, twice as stiff and lasts much longer" I'm skeptical. It looks like ipe has a modulus of rupture about 2.5x that of pine and is substantially more rot resistant. So even with the extra 1/4" of thickness for a 2x piece the ipe is still going to be stronger (1.5^3/1.25^3 = 1.73 [in favor of the pine] but 177.0 MPa/71.0 MPa = 2.5 [in favor of ipe]). It looks like ipe still comes out ahead. – Brad Jun 15 at 17:15
  • I was comparing pine to pine of different thickness . Ipe looks like a very strong very expensive wood. – blacksmith37 Jun 15 at 19:46

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