exterior deck-how to DIY a ceiling ?

rfuerst911sc · 12-26-2018, 03:02 AM

So I did an internet search and found companies that will install an under deck . Looks great but also looks expensive . So that got my DIY brain churning

. I found local to me someone selling fiberglass panels 3 ' x 7 ' for a buck apiece so that is a cheap way to go for the ceiling material . But how do you slant the ceiling for water runoff ? Obviously you have to attach something to the bottom of the deck joists but what ? Do you just rip a 2x at a taper lengthwise ? Basically making a long tapered wedge ? I have two sections of deck that are about 20 ' wide and project out from the house about 16 ' , those two areas would be great for storing bulk items if I can get the water to stop dripping in those areas . Any ideas or pics would be helpful .

KFC911 · 12-26-2018, 03:19 AM

I contemplated doing something similar years ago. Great way to trap debris, raise critters, spiders, etc. imo....never did anything.

When you get it figured out....I'm subscribed

!

drcoastline · 03:25 AM

The first question in order to answer your question is, Do you already have a roof over your deck?

Question number two if so how is it constructed?

Edit" Maybe I am misunderstanding your question? Is this to install a ceiling above the deck or below the deck?

rfuerst911sc · 12-26-2018, 03:42 AM

drcoastline we do not have a roof over the deck , and yes I want to install a ceiling under the deck to control the water that drips through the gaps of the deck boards . In regards to trapping debris/spiders/critters not too concerned about that , how much stuff is really going to fall through 1/8th - 1/4 " gaps in the deck boards ? But I see the point of the comment . I was even thinking of installing cheap aluminum gutter at the very end of the ceiling , space it so the ceiling panels actually rest on the gutter . This would make it much harder for larger critters ( birds , bats , etc. ) from getting into the space . And the gutter would channel the water away vs. just having it drip on the ground at the ceilings edge .

drcoastline · 03:52 AM

Quote:

Originally Posted by rfuerst911sc

drcoastline we do not have a roof over the deck , and yes I want to install a ceiling under the deck to control the water that drips through the gaps of the deck boards . In regards to trapping debris/spiders/critters not too concerned about that , how much stuff is really going to fall through 1/8th - 1/4 " gaps in the deck boards ? But I see the point of the comment . I was even thinking of installing cheap aluminum gutter at the very end of the ceiling , space it so the ceiling panels actually rest on the gutter . This would make it much harder for larger critters ( birds , bats , etc. ) from getting into the space . And the gutter would channel the water away vs. just having it drip on the ground at the ceilings edge .

OK, after I reread that is what I thought. You need to be concerned about what falls through and spiders the webs specifically as they will grab and hold the debris. By putting a ceiling under there you will trap all that debris and it will be a lot. It will pile up in the corners where the ceiling meets the joists. That in turn will absorb moisture as will the joists. This will cause a rot issue and or cause premature failure of the fasteners.

Before installing ceiling you are going to want to water proof the decking. Such as a fiberglass deck.

It's not a very good idea at this time.

URY914 · URY914's Garage

We need a picture

drcoastline · 12-26-2018, 03:55 AM

To answer your question directly. Your deck should already have a pitch so you shouldn't need to do anything other than fasten the FG to the bottom of the joist.

Crowbob · 12-26-2018, 04:34 AM

I have the same situation. I decided a ceiling under the entire deck (mine is 17x23 or so) would be a perfect hideout for birds, critters, bugs, leaves, etc. So, I’m thinking a couple of panels of sloped corrugated fiberglass/plastic panels suspended by chain would allow the occasional cleaning, probably annually.

At least some of the area under the deck would be dry.

I’ve considered long wedges under each joist but wood would crack and/or split over time.

I haven’t done anything, yet.

rfuerst911sc · 12-26-2018, 04:48 AM

Paul I just took a few pics I'm waiting for them to upload . DR no the deck does not have much pitch to it and I wouldn't expect it to . You want a flat surface to walk on , put furniture on and grills on . Isn't part of the reason for a gap along each board for water runoff ? Crowbob I hear what you are saying but I'm a stubborn person haha ! I'm thinking the wedge/s will NOT be made of wood they can be composite to virtually eliminate rot . And I want to have enough " pitch " for the majority of water that drips through the deck boards will run out vs. puddle . There will be no place for birds to get in , the house side and the two ends will be closed in . The open end I can install 1/8th " hardware cloth so plenty of ventilation and will keep large stuff out . Our house has gutters so nothing coming off the roof goes onto the deck . The nearest trees are 70 ' + away from the house in one year living here I have not seen one leaf or pine needle on our deck so I don't think there will be tons of debris going onto the ceiling . I do enjoy this discussion because it's possible I am crazy for this idea !

rfuerst911sc · 12-26-2018, 05:01 AM

Here are the pics , let me know if any questions . This is one side of what I want to install a ceiling on .

cabmandone · cabmandone's Garage

Just buy 2x4's the length of the run, cut a notch for the bridging supports and screw the 2x4 to the side of the existing joist at an angle that allows water to flow away and attach your panels. Then as you mentioned, put a gutter at the end to direct the water away.

BTW, have you put a level on the deck floor? Some decks will be pitched away from the structure.

jyl · jyl's Garage

Quote:

Originally Posted by cabmando

Just buy 2x4's the length of the run, cut a notch for the bridging supports and screw the 2x4 to the side of the existing joist at an angle that allows water to flow away and attach your panels. Then as you mentioned, put a gutter at the end to direct the water away.

BTW, have you put a level on the deck floor? Some decks will be pitched away from the structure.

I typed up a convoluted idea but deleted it because cabmando's makes more sense.

drcoastline · 07:51 AM

Quote:

Originally Posted by rfuerst911sc

Paul I just took a few pics I'm waiting for them to upload . DR no the deck does not have much pitch to it and I wouldn't expect it to . You want a flat surface to walk on , put furniture on and grills on . Isn't part of the reason for a gap along each board for water runoff ? Crowbob I hear what you are saying but I'm a stubborn person haha ! I'm thinking the wedge/s will NOT be made of wood they can be composite to virtually eliminate rot . And I want to have enough " pitch " for the majority of water that drips through the deck boards will run out vs. puddle . There will be no place for birds to get in , the house side and the two ends will be closed in . The open end I can install 1/8th " hardware cloth so plenty of ventilation and will keep large stuff out . Our house has gutters so nothing coming off the roof goes onto the deck . The nearest trees are 70 ' + away from the house in one year living here I have not seen one leaf or pine needle on our deck so I don't think there will be tons of debris going onto the ceiling . I do enjoy this discussion because it's possible I am crazy for this idea !

It has some pitch probably 1/4" in 12" based on what it looks like in the photos. This is enough to get water to run off the deck and away from the house. The gaps are to get water to run off the decking and designed to fall to the ground. Again to your direct question, you can attach directly to the bottom of the joists. The pitch will allow the majority of the water run off. However friction will hold water in the area where the FG panels and joists are attached and the debris that falls through the gaps will also collect water and that will cause water to begin to stand. A little in the beginning and it will increase as time goes by.

Again, I am going to caution you. You already have a moisture/humidity problem. See the green slime? That is a high humidity issue. If you enclose the joists you are going to exponentially increase that problem. In the summer that will become a mold incubator.

Edit:, add a sleeper to the bottom of the joist so you clear the bridging.

VincentVega · 12-26-2018, 08:12 AM

Really think about what drcoastline brought up. You will have moisture issues. You will have debris issues. You need to figure out how to get airflow through the area or it will rot quickly.

dad911 · 12-26-2018, 09:14 AM

How old are the deck boards? If they are nearing end of life, rip them off, plywood, and fiberglass the whole deck.

rfuerst911sc · 12-26-2018, 10:09 AM

The house was built in 1996 we bought it last year , for all I know the deck boards could be from then . And they do need to be replaced . In regards to the slime yes it is there and could have been growing since 1996 . I just haven't had a chance to break out the pressure washer to clean it up .

If the boards were pulled up and replaced with plywood how would you water proof that surface ? Yes I put a 4 ' level on the deck and it does have a slight pitch away from the house . Maybe a better idea is to just put a storage shed under the two sections . It just seems like a huge waste of space but I don't want to ruin the floor joists .

dad911 · 12-26-2018, 10:15 AM

We pay about $10/foot for fiberglass over plywood.

https://www.deckmagazine.com/design-construction/decking/installing-fiberglass-roof-decks_o

cabmandone · cabmandone's Garage

Quote:

Originally Posted by rfuerst911sc

The house was built in 1996 we bought it last year , for all I know the deck boards could be from then . And they do need to be replaced . In regards to the slime yes it is there and could have been growing since 1996 . I just haven't had a chance to break out the pressure washer to clean it up .

If the boards were pulled up and replaced with plywood how would you water proof that surface ? Yes I put a 4 ' level on the deck and it does have a slight pitch away from the house . Maybe a better idea is to just put a storage shed under the two sections . It just seems like a huge waste of space but I don't want to ruin the floor joists .

I'd increase the pitch by doing what I suggested in the other post and leave the ends open so air can flow. Use treated lumber when attaching to the sides of the existing joists. If you can get the fiberglass panels cheap enough, I'd give it a go rather than spend the money on a storage shed.

MBAtarga · 03:41 PM

I used metal roofing in 12’ lengths to do exactly what you are trying. Mine was under a section of deck that was only 8’ wide though but about 30’ in length. I used 2x4 framing to form U shaped supports that the roof tins rested on and even had a section of rain gutter with downspout that tied into an existing downspout drain at the deck corner. Each U section was spaced about 4’ apart and was of decreasing height to slope the tins and water to run off. The deck was enlarged and enclosed 2 years ago and I removed the structure so I’ve got no pictures to share.

Sent from my iPhone using Tapatalk Pro

cabmandone · cabmandone's Garage

Something else you could do which would probably be easier, if you have a planer, make a 1/2" furring strip, then 7/8 then a 1.5" board and run them the opposite way the joists run. It looks like you have about a 10 -12' span and the added pitch would increase drainage. Before you add the ceiling, use treated wood cleaner and then seal the joists using a pump sprayer.