FHB Logo Facebook LinkedIn Email Pinterest Twitter X Instagram Tiktok YouTube Plus Icon Close Icon Navigation Search Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Subscribe
Log In
  • How-To
  • Design
  • Tools & Materials
  • Restoration
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
Log In

Discussion Forum

Discussion Forum

Mahogany porch construction

andybuildz | Posted in Construction Techniques on May 11, 2006 03:12am

I’ll be laying down three 5/4 x 4 T&G mahogany porches in a cpl of weeks.

Two of the porches are over the ground but one is on a second floor over one of the other porches.  PICTURES ATTACHED

The underside of the 2nd fl. porch I’m using beadboard soffet.

Originally I was going to go over some 3/4″ Advantech I laid down while framing. Was gonna put down a rubber torch down roof under 5/4 x 4 sleepers…naturally the whole roof will slope away from the house approx 1/4″ per foot (Porch goes out 8′ (8×18).

Thing is I framed the porch up too high…ugh…I have approx 4″ from the top of the Advantech to the entry door. I really don’t want less than 4″ from the top of the finished mahogany porch to the floor in the house because snow and rain seem to beat that side of the house most frequently. Am I being overly paronoid?

Can I use the t&g mahogany with nothing under it. Nail directly to the floor joists?

Will it leak water onto the soffet and deck below? Or will it stay relatively dry below like a boat keeping out the water?

Or am I in a dillusional dream land? OK forget that…the question above then ~~

Am I being too paronoid about having only about 1 1/2″ above the mahogany porch floor on 5/4 x 4 sleepers?

thanks

a…

If Blodgett says, Tipi tipi tipi it must be so!

TipiFest 06~~> Send me your email addy for a Paypal invoice to the greatest show on earth~~>[email protected]

Reply
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles

Replies

  1. mike585 | May 12, 2006 12:58am | #1

    I have porches that are 5/4x4 mahagony on pressure treated joists, 16" on center. I think you'll be ok. I have vented crawlspace below mine. My problem is that they are hard to keep finished. The sun and rain and winter weather is tough on them. They will buckle if the wood gets wet; it happened to mine.

    "With every mistake we must surely be learning"
    1. WNYguy | May 12, 2006 01:10am | #2

      Mike, I've been hoping someone would reply, as I have a potentially similar situation.  Do you think water infiltration will be a problem for the ceiling of the lower porch?  Can it be solved by venting that space somehow?  If a pile of melting snow sits on that upper deck, some water will surely find a way down through the floor boards, won't it?

      Allen

      1. mike585 | May 12, 2006 03:25am | #3

        I'm a few hours east of you and I can tell you that this is not the material for a weather exposed porch floor in the northeast.  I have redecked this porch, sealing all 6 sides of each piece and applying spar poly. It's ok under the covered parts of the porch but where the sun and rain gets to it it's not good. I would not count on the T&G flooring to be water tight.

        It kills me because I like the look of the natural wood but I have found myself looking at the synthetic materials more and more.  If you come up with a plan let me know and I'll try it.  I've looked at T&G fir as an alternative. I don't know if that would work better.

        I'm interested in knowing how your career change is going and whether you have cleaned up that shop yet. I suppose if it's not cleaned up then you are busy and the venture is going well.

         

         "With every mistake we must surely be learning"

        1. johnharkins | May 12, 2006 04:00am | #5

          I tend to think you are in for a recurring nightmare w/ any uncovered porch w/ t & g decking /// but definitely for that one upstairs that you and your better half will most likely be the main visitors give a look to Resource Conservation Technology 410 366 1146 and their websiteI'm doing kinda a bigger renovation like yours and the last thing you want to be doing ( when you still have a multitude of new things to do ) two yrs from now is renting a floor sander to re do your t&g mahogany because it no longer resembles what you beautifully installed less than two yrs agotake it back & use the proceeds to flank your pool w/ some of Mike Smith's bluestone

        2. WNYguy | May 12, 2006 04:15pm | #9

          Hey, Mike, thanks for the input.  I don't want to hijack this thread; I think Piffin addressed most of my concerns.

          I'm not using mahogany, but I need to install a floor on a second-floor porch deck.  I've already installed a tongue-and-groove beadboard ceiling directly to the bottom of the joists.  My concern is water infiltration from the floor above.  There is a roof above the second-story deck, which offers some protection.

          Photo is attached below.  It's a 1915 classical revival porch on an 1870s house.  To me it looks like a silly anachronym; if it were my house I would rip it off and build an appropriate Italianate porch.

          RE: Career change.  I have more work than I can keep up with; clients on a waiting list already.  But I still feel like a hack ... I work too slowly and my craftsmanship is not to the level I want.  I'm short on tools and that slows me down, too.  Way undercapitalized, and can't afford new tools.  Truck broke down, and repair bill ate any profits I might have had so far.   After working nights (newspaper newsrooms) for 23 years, getting out the door in the morning is still tough.  Bottom line:  Happy to be working on my own, happy to be home at night with my beautiful wife.

          Allen

           

        3. dustinf | May 14, 2006 04:22am | #16

           sealing all 6 sides of each piece and applying spar poly. It's ok under the covered parts of the porch but where the sun and rain gets to it it's not good.

          I'm having the same problem with a deck that I built in the fall.  It's less than six months old, and the finish has completely dulled.  The deck is on the southern side of the house, and has constant sunlight.  I've tried Cabot's timber oil, and that didn't last long.  The next coat is going to be Waterlox, but I have my doubts about it.Doncha wish your girlfriend was hot like me?

  2. Danusan11 | May 12, 2006 03:57am | #4

    Andy, had a similar situation on a job I bid on. They make a vinyl product that fits between your joists, that has a slight v shape in center. You tuck it up inside bays and fasten with a pitch to end. Snaps into a channel similar to siding.

    I planned on then installing bead board and leaving a 1/2" open at end. And taking strips of grace to fold over joists and drop down over channels.

    If it sounds like something that might interest you let me know and I'll stop at lumber yard and get you the info.

     

    1. andybuildz | May 12, 2006 03:08pm | #8

      Dan...yeh, thanks. I'd appreciate if found out the name and I'll look it up online. Don't go out of your way though cause I have a feeling I may do the torch down and then the sleepers being the joists arent running the way I want them to to run my mahog lengths which is front to back rather than side to side anyway, i totally F'd up when I did that upper deck. Now I ned to deal with it.If Blodgett says, Tipi tipi tipi it must be so!

      TipiFest 06~~> Send me your email addy for a Paypal invoice to the greatest show on earth~~>[email protected]

      1. Danusan11 | May 13, 2006 04:55pm | #12

        Andy. Type in (Dry space deck drainage solutions) and it will bring you to the product I was telling you about

  3. Piffin | May 12, 2006 04:32am | #6

    I had a long and varied conversation a couple years ago witha wood scientist who works witha major NE broker/supplier of lumber.

    T&G should never be used on an exposed deck with no roof over it. When it has a roof over it but water can still be blown in on it, you need to preseal all four sides before laying it and then plan to recoat at least every two years, with once a year being preferrred.

    your original plabn was the right one. Make a real roof, then sleeprs to allow drainage and breathing - then use square edged lumber.

    The other choice is do what you are thinking of - every 5-6 years

     

     

    Welcome to the
    Taunton University of
    Knowledge FHB Campus at Breaktime.
     where ...
    Excellence is its own reward!

    1. andybuildz | May 12, 2006 02:52pm | #7

      Thanks...I remember we all spoke about this a ways back...maybe fifty times already...lol. It was the exposed T&G issue I was wondering about mainly and the height from deck top to door threshold top.
      Its a drag cause I was thinking I shouldn't do the top porch w/t&g but I guess I got caught up in the t&g state of mind and didnt stay with reworking the top deck ideas. It happens...I HATE when that happens. Oh well. At least its not a huge deck up there.
      I spose being I already paid for it to be milled...its mine so I may as well just go ahead and use it and what happens will happen. I'll do the torch down under it. I already soaked all sides with Cabotts Aussie Oil. That bay trough sounds interesting though...I'll have to find out about that as long as I'm experimenting.
      Can I run the sleepers from side to side if the roofs pitched front to back so I can get the mahogany lengths running front to back? Leave spaces between lengths of sleeps like weep holes? No that much water should be getting in there anyway...I hope...oiy.
      Doncha hate when ya dont plan everything perfectly? Maybe I should build a roof over it or make it sod...
      Hey I could care less i I have to rent the sander for two hours every other year. It'll be like I built a new deck...kinda like trading in your car.If Blodgett says, Tipi tipi tipi it must be so!

      TipiFest 06~~> Send me your email addy for a Paypal invoice to the greatest show on earth~~>[email protected]

      1. Piffin | May 13, 2006 07:02am | #10

        yeah, run the sleepers with one ich gaps between them to faacilitate drainage.For smaaller landing decks, I haave use gorilla glue in the T&G joints to make for a water resitnt seal 

         

        Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

        1. andybuildz | May 14, 2006 04:00am | #15

          Gorilla glue????????? You kidding?
          I never thought you could do that.
          PL Premium better? No expansion and easier to apply?If Blodgett says, Tipi tipi tipi it must be so!

          TipiFest 06~~> Send me your email addy for a Paypal invoice to the greatest show on earth~~>[email protected]

          1. Piffin | May 14, 2006 05:32am | #18

            PL Premium does expand moderately, but that's the point of it. The expanding glue fills the gaps in the T&G that would otherwise hold water and hasten rot. 

             

            Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

          2. andybuildz | May 14, 2006 05:38am | #19

            Did you just spread the glue in the groove? Didnt it run out at the top anywhere?
            Doncha think you could use PL Premium with pretty much the same effect and less mess?? Or no?If Blodgett says, Tipi tipi tipi it must be so!

            TipiFest 06~~> Send me your email addy for a Paypal invoice to the greatest show on earth~~>[email protected]

          3. Piffin | May 14, 2006 07:33am | #20

            The advantage of the Gorilla glue is that what oozes out can easily be scraped away. Not so with PL premium.I run the bead of glue on the upper portion of the tongue I just nailed down, then fit the new groove to it. That places most of the glue in the top third of the thickness and in the groove itself, withjout too much in the lower third 

             

            Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

          4. andybuildz | May 14, 2006 01:17pm | #21

            This whole upper deck situation is going against my better judgement but yes....I'm still gonna do it anyway. Its my personal experiment...lol.
            As many times as gluing the deck together ran through my mind I quickly relinquished any thought of entertaining that idea. Just didn't seem at all right. Almost as wrong as some people thinking its not cool to glue a finished floor to a subloor which I've done successfully a dozen times and better.
            Soooooo...I may as well drizzle a nice bead of Gorilla Glue on my broa...I mean boards tongue : )~
            I'll end up PortaCabling (sanding) the whole floor cause of you....
            I can see it now...drizzle a hair line bead and come back to see white foam all over the red mahogany and Geppetto out there with a chisel all day.......lol.If Blodgett says, Tipi tipi tipi it must be so!

            TipiFest 06~~> Send me your email addy for a Paypal invoice to the greatest show on earth~~>[email protected]

          5. Piffin | May 14, 2006 05:31pm | #22

            well,Yeah!;) 

             

            Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

      2. wrudiger | May 14, 2006 08:36pm | #23

        "I already soaked all sides with Cabotts Aussie Oil"

        Ouch!  Sorry, man, plan on a refinish with a real deck sealer before winter sets in.  Guarantee the Cabotts will be long gone by fall.  Mine lasted less than 4 months on any exposed area, here in mild central CA.  IMHO the Cabots is in a dead heat with Thompson's Waterseal as the most useless product on the market.  Posts on a number of boards say I'm not alone...

        If you can still get the good stuff (Waterlox, TWP 100 series, ...) where you are, go for it!  VOC regs in CA really restrict our options.

        1. andybuildz | May 15, 2006 03:27am | #24

          actually I mispoke. I didnt seal all the deck four sides. Just the few steps I put up. I may just switch to Waterlox or Penofin.If Blodgett says, Tipi tipi tipi it must be so!

          TipiFest 06~~> Send me your email addy for a Paypal invoice to the greatest show on earth~~>[email protected]

          1. dustinf | May 15, 2006 05:51am | #25

            I've had some bad experience with Cabot's recently.  I'm beginning to regret it now that the sun is getting higher in the sky.Hate me today, hate me tomorrow, hate me for all the things I didn't do.

          2. andybuildz | May 15, 2006 06:17am | #26

            FWIW no wood oil is gonna last more than a year or two......

            Penofin's "marine"oil finish according to them lasts 1-2 years...so my guess is one year tops under normal conditions.

            I think we're talking the differance of a few months here.

            I still dont know if I'll stick with the Aussie Oil or go to Penofin...I still have almost a full gallon of the aussie mix.Sure looks nice this week on those steps....by the time I get to doing the porches I'll have had plenty of time to see how the stairs are holding up. That should be a good barometer.

            The OFC laws doesn't allow the good stuff any where near here so...

            I should do the rear poches and the front in different finishes and see what happens over a year...Katrina will love that...lol.If Blodgett says, Tipi tipi tipi it must be so!

            TipiFest 06~~> Send me your email addy for a Paypal invoice to the greatest show on earth~~>[email protected]

  4. MikeSmith | May 13, 2006 03:23pm | #11

    andy... you need the sleepers

    4" should be ok... even 2" if you have a good panflash under the doors

    and you need the pitch on the advantech subfloor

    so.. if i understand:

    2d floor porch floor joists, with 3/4 advantech subfloor are pitched away from the house, top of subfloor is 4" below finished interior 2d floor

    you will do torch down on this...

    the 5/4 uses 1".. so now you 3" drop left....  if you carefully screw your decking to the sleepers , you might get by with 5/4 sleepers next to the door.. leaving you with  2" finish decking top below the interior finished 2d floor

    make sure your torch down turns up to the bottom of the door sill , and the pan flash goes over the top

    also make sure nothing can block the sleeper path to creat a future dam

    i like to make the decking in panels so you can lift the panels and clean debris , or make repairs to the torch down if you have to

    the sleepers will be tapered  ( 8' x 1/4" per foot = 8/4 = 2" )  so your sleepers will taper from  5/4  at the door  to 13/4 at the porch edge.. the decking lays parallel to the house.. and the water runs between the sleepers to the roof edge

    if you are using scuppers you need  cross channels  for the water to run sideways to the scuppers

    if the outer porch  wall is not solid, then you don't need scuppers and the roof edge can sheet drain

    Mike Smith Rhode Island : Design / Build / Repair / Restore
    1. andybuildz | May 14, 2006 03:54am | #14

      Thanks Mike..
      No, not doing scuppers. Wasn't gonna taper sleepers either. I just dropped the porch floor to about 1 1/2" in 8' which seems to be pretty good. It just rained for two days and theres no water up there to speak of.
      And yeh...Gonna torch down some rubber sheet and go up under the door sills then bend some copper to go under the door sills over the rubber as well.<<<<<<<also make sure nothing can block the sleeper path to creat a future dam >>>>>>>Thing is like I said to Piff...I want the mahogany lengths to go front to back the way the deck is pitched which means the sleepers would have to go side to side which concerns me but if I leave 1" or so weep holes every 4 ft or so I think I should be good. I'm not "expecting" any serious amt of water to get through the T&G. Sound right?
      OR
      So you think it'd look ok withthe 1x4 t&G going side to side??
      I kinda thought porch floors look better going the way you walk out the door. I donno??? I'm so confused...lol.
      Thing is...I "really" wish I'd have maybe gotten a composite decking for up there. I just got so caught up in wanting to do it all in wood and all in a porch style (t&G). Spose it wouldn't be horrible to have to sand up there every cpl a years (tell that to a new owner : )Thanks again MikeIf Blodgett says, Tipi tipi tipi it must be so!

      TipiFest 06~~> Send me your email addy for a Paypal invoice to the greatest show on earth~~>[email protected]

      1. MikeSmith | May 14, 2006 04:26am | #17

        andy... when i saw 5/4 mahogany i thought square edge with spaces between the boards

        with the T&G , i'd  do just as you are going to do.. front to back with the  weep NOTCHES every two feet or soMike Smith Rhode Island : Design / Build / Repair / Restore

  5. RPC | May 13, 2006 06:24pm | #13

    Fine Homebuilding has publised two articles on the subject of roof decks.  You will find them in the archive section of this web site (might cost you $5.00.  I read both articles prior to installing a Mahogany roof deck in Boston and found the articles to be insightful.

    RPC - Erie PA

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Video Shorts

Categories

  • Business
  • Code Questions
  • Construction Techniques
  • Energy, Heating & Insulation
  • General Discussion
  • Help/Work Wanted
  • Photo Gallery
  • Reader Classified
  • Tools for Home Building

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Up Next

Video Shorts

Featured Story

Podcast Episode 694: Bath Fans, Too Many Minisplits, and Second-Story Additions

Listeners write in about fire-rated doors, using seven minisplits for cooling, and how to build a second-story addition.

Featured Video

Micro-Adjust Deck-Baluster Spacing for an Eye-Deceiving Layout

No math, no measuring—just a simple jig made from an elastic band is all you need to lay out a good-looking deck railing.

Related Stories

  • Repairing a Modern Window Sash
  • Landscape Lighting Essentials
  • Podcast Episode 694: Bath Fans, Too Many Minisplits, and Second-Story Additions
  • FHB Podcast Segment: Can You Have Too Many Minisplits?

Highlights

Fine Homebuilding All Access
Fine Homebuilding Podcast
Tool Tech
Plus, get an extra 20% off with code GIFT20

"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Fine Homebuilding Magazine

  • Issue 332 - July 2025
    • Custom Built-ins With Job-Site Tools
    • Fight House Fires Through Design
    • Making the Move to Multifamily
  • Issue 331 - June 2025
    • A More Resilient Roof
    • Tool Test: You Need a Drywall Sander
    • Ducted vs. Ductless Heat Pumps
  • Issue 330 - April/May 2025
    • Deck Details for Durability
    • FAQs on HPWHs
    • 10 Tips for a Long-Lasting Paint Job
  • Issue 329 - Feb/Mar 2025
    • Smart Foundation for a Small Addition
    • A Kominka Comes West
    • Making Small Kitchens Work
  • Issue 328 - Dec/Jan 2025
    • How a Pro Replaces Columns
    • Passive House 3.0
    • Tool Test: Compact Line Lasers

Fine Home Building

Newsletter Sign-up

  • Fine Homebuilding

    Home building tips, offers, and expert advice in your inbox.

  • Green Building Advisor

    Building science and energy efficiency advice, plus special offers, in your inbox.

  • Old House Journal

    Repair, renovation, and restoration tips, plus special offers, in your inbox.

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters

Follow

  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X
  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Privacy Preferences
  • About
  • Contact
  • Advertise
  • Careers
  • Terms of Use
  • Site Map
  • Do not sell or share my information
  • Privacy Policy
  • Accessibility
  • California Privacy Rights

© 2025 Active Interest Media. All rights reserved.

Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

  • Home Group
  • Antique Trader
  • Arts & Crafts Homes
  • Bank Note Reporter
  • Cabin Life
  • Cuisine at Home
  • Fine Gardening
  • Fine Woodworking
  • Green Building Advisor
  • Garden Gate
  • Horticulture
  • Keep Craft Alive
  • Log Home Living
  • Military Trader/Vehicles
  • Numismatic News
  • Numismaster
  • Old Cars Weekly
  • Old House Journal
  • Period Homes
  • Popular Woodworking
  • Script
  • ShopNotes
  • Sports Collectors Digest
  • Threads
  • Timber Home Living
  • Traditional Building
  • Woodsmith
  • World Coin News
  • Writer's Digest
Active Interest Media logo
X
X
This is a dialog window which overlays the main content of the page. The modal window is a 'site map' of the most critical areas of the site. Pressing the Escape (ESC) button will close the modal and bring you back to where you were on the page.

Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Project Guides
  • Reader Projects
  • Magazine
  • Members
  • FHB House

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

Online Learning

  • Courses
  • Project Guides
  • Reader Projects
  • Podcast

More

  • FHB Ambassadors
  • FHB House
  • Customer Support

Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Follow

  • X
  • YouTube
  • instagram
  • facebook
  • pinterest
  • Tiktok

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 70%

Subscribe

Enjoy unlimited access to Fine Homebuilding. Join Now

Already a member? Log in

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in

Privacy Policy Update

We use cookies, pixels, script and other tracking technologies to analyze and improve our service, to improve and personalize content, and for advertising to you. We also share information about your use of our site with third-party social media, advertising and analytics partners. You can view our Privacy Policy here and our Terms of Use here.

Cookies

Analytics

These cookies help us track site metrics to improve our sites and provide a better user experience.

Advertising/Social Media

These cookies are used to serve advertisements aligned with your interests.

Essential

These cookies are required to provide basic functions like page navigation and access to secure areas of the website.

Delete My Data

Delete all cookies and associated data