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kawerkamp

Any possible way to install an ipe porch over concrete cap?

kawerkamp
6 years ago

We are building a new home and I had my heart set on a hardwood (ipe or cumaru) front porch....until I called an ipe supplier yesterday and he strongly discouraged me from doing a hardwood deck in our situation.

Here was the plan: We live in Idaho with a high mountain desert climate--extreme winter temperatures and dry. This porch goes over our basement cold storage, which will be covered with a concrete cap that is water-sealed and sloped for drainage (there should be very little water getting into the deck anyway because the porch is entirely covered). We were going to face-screw 5/4"x6" ipe decking on 2x6 sleeper joists so that the wood wouldn't sit directly on concrete, but the decking supplier said that 6" is still way too close to the concrete cap for proper ventilation (they recommended a minimum of 18"!). He was also not keen on us wrapping the porch face with a stone fascia to meet HOA masonry requirements (we were going to drill in weep-holes to allow for any drainage from the sloped concrete cap so that moisture never accumulates). I have no interest in a synthetic, trex-like decking material, so he recommended ipe tiles as a much more stable alternative that wouldn't cup and can go directly on concrete, but those don't fit with the old-fashioned porch aesthetic we're going for at all.

Before I bury the dream of a real wood porch, I wanted to reach out to the Houzz community to see if anyone has installed ipe or other hardwoods over a concrete cap? If so, how did you ensure proper ventillation, and have you had any issues with boards cupping? If we do have to wrap the porch with stone facing, any advice on how to do so in a way that doesn't exacerbate cupping risks? Thank you!

Comments (12)

  • PRO
    SolusLumber.com
    6 years ago
    last modified: 6 years ago

    PS. Just spoke with a mentor/competitor/also a direct ipe importer who has forgotten more about wood than we will ever know and bounced your dilemma off of him. He pretty much agreed with us. 5/4x4 KD ipe on sleepers should be fine in your application. He did add, and we concur, that you make your gap between boards 5/32 not 3/32. He said you could also add floor vents back towards the wall if it made you feel better, but probably not necessary particularly if there is a roof over the porch. Also said if it was his personal deck, in your climate, he'd go 16" OC but that "maybe the CYA (cover your ass) factor dictates 12" OC"

    kawerkamp thanked SolusLumber.com
  • kawerkamp
    Original Author
    6 years ago
    last modified: 6 years ago

    BLESS you! This is exactly the kind of info I was hoping for (and it was especailly kind of you to solicit the second opinion of your colleague too!) We will definitely face-screw and can ventilate exactly as you recommended. I’ll go for the 5/4” thickness.

    I do like the wider 6” boards more than the 4” (less busy)—if we are face screwing with 12” OC joists, do you still think 4” width is the only safe way to go or would we be okay with the 6” width? I’m also wondering if we should place our sleeper joists on 1-2” spacers (instead of directly on the concrete—to basically get the effect of the pedestals in the pictures you included) to allow for air flow across joist channels? Finally, when you suggested “maybe use one board of fascia along edge?" was that for drainage purposes (the concrete below will be sloped and feed out any water through a weep hole in the masonry) or for ventilation? If it's for ventilation reasons, are you suggesting something like this photo where they have a fascia board topping their brick skirt? (incidentally this porch is 1x6 cumaru decking in Florida....really similar to the look we're going for!) If so, how exactly would the fascia at the top allow for more ventilation than if we pulled the masonry all the way to the underlip of the decking?

    Exteriors · More Info

  • PRO
    Archatrak Inc.
    6 years ago

    Hi Kowercamp, I think an Ipe wood pedestal paver system could work nicely for you and might end up quite cost effective when all things are considered. A 24x48" paver might give you more of the elongated feel you are after, take a peak here:https://www.architrex.com/products/structural-wood-tiles/structural-wood-tiles/

    kawerkamp thanked Archatrak Inc.
  • PRO
    SolusLumber.com
    6 years ago
    last modified: 6 years ago

    Wonderful! But don't bless us until after the job has been declared a success!

    We're going to stick with our 5/4x4 recommendation. Historically porches are usually x4 as well. It is a little "busier", but two weeks after install you won't notice or think about it. (Along with the bathroom faucets, door knobs and everything else it's so easy to hyper focus on when building a new home... this comes from personal experience)

    All the following jobs Miami/Bahamas/Sarasota/Palm Springs were slapped down on grade and the customers (against recommendation) went with 5/4x6 and it worked out ok.... but those are your dice to roll.

    Spacers definitely aren't going to hurt anything. The more height you can squeeze out of it the better off you will be.

    The fascia board.... its both a drainage and ventilation issue. I would defer to a builder and code on this one, but intellectually here's the logic. If you bring up the stone right to the bottom edge of the deckboards then drill weep holes you're basically closing in the edge of the porch tight with little room for airflow with the exception of the weep holes. Instead, if you bring the stone up to the edge of the concrete then extend your porch and sleepers just a little beyond the edge of the concrete/stone then have a fascia board (like in the photo you posted from Dalrymple Sallis Architecture) the air will flow up behind the board then under the deck for the entire length of the face of the porch instead of just at the weep holes. Additionally, though probably not necessary, it would also afford you the opportunity to add vents into the fascia. Not very aesthetically pleasing, but if you're planning on adding landscaping in front like bushes/shrubs then they may end up hidden anyway......

    5/4x6 Garapa Miami, FL · More Info

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    kawerkamp thanked SolusLumber.com
  • kawerkamp
    Original Author
    6 years ago
    last modified: 6 years ago

    Got it, SolusLumber! I can sooo relate to the hyper-focus advice (just finished ordering our windows--never paid so much attention to my own and other people's windows until now!)

    So, would you point me toward ipe, cumaru, garapa or something else in our situation (I see SolusLumber sells many different hardwood varieties on the website), esp if I throw caution to the window and do the 6" width (coloration doesn't matter because we plan to let it age and silver out, so all I care about is cost and cupping risk)? And should we throw pea-gravel or anything over our concrete pad before putting on the deck (we are planning to apply a water sealant membrane on the concrete first), or just leave it as concrete and air under the decking so that any water will drain out unobstructed?

  • PRO
    SolusLumber.com
    6 years ago
    last modified: 6 years ago

    So we'd strongly direct you towards 5/4x4 Ipe KD. As you stated, since you plan to let it weather to a silver/grey, the natural color of the wood doesn't matter since they will all weather to the same silver/grey color. You do raise a point that we forgot to mention earlier.... we always recommend one coat of oil after initial install to help the wood acclimatize. Super easy process and if you go to the video gallery on our website there is a video on "How to Oil". https://www.soluslumber.com/gallery-how-to-videos/ After that then let it weather grey.... as far as the peastone on top of the concrete goes that's probably unnecessary. It will only serve to trap moisture. Beyond that it's about cost and cupping....

    kawerkamp thanked SolusLumber.com
  • kawerkamp
    Original Author
    6 years ago

    How significant is the difference in cupping risk between 5/4x4 and 1x4 boards?....the pricing on the 5/4x4 is pushing our budget too far. I've also seen several suppliers offering "1 plus" x 4 as an affordable alternative to 5/4....is that going to be significantly better than the 1"? (The 5/4x6 was perfect for our budget of reduced material and labor costs, but if it poses too a high cupping risk, we'll go with the 4"width, just need to figure out how thick.)

  • PRO
    SolusLumber.com
    6 years ago

    Stick with the 5/4x4. 5/4x4 is cheaper per linear foot, but it does require more l/ft of to cover the same surface area than if it was 5/4x6. Give us a call and let's see if we can talk you through it and find you a solution.

  • kawerkamp
    Original Author
    6 years ago

    Will do, Solus.


  • HU-813193270
    4 years ago

    So I have a client with a similar situation. The difference being that they want to maintain a wood deck on a second floor balcony with interior rooms under 10' of each end of the balcony on the 1st floor causing us to need to waterproof the wood sub decking before finished wood goes on top. we also don't have room to raise the floor at the doors going onto the balcony. Our thought for water proofing was to slope the sub-balcony floor and waterproof with a non-granular Soprema roof system then add IPE directly onto of the Soprema using an additional elastomeric product (Vulkem) to ensure waterproofing. Would we be making a huge mistake and what other alternative species of wood might be better?

  • PRO
    ElementLumber.com
    4 years ago

    Ipe would probably be the best wood. Probably too late to chime in, but what’s the minimum height at the door that needs to be met? Would not recommend putting the Wood right in the membrane, but could definitely utilize a pedestal system that helps ensure the waterproof membrane isn’t permeated and allows you to use a traditional decking product...