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Old 12-28-2020, 03:59 PM   #1
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Attic vents in a camper, what are they and what do they do?

A camper attic vent is a roof vent installed on the top of the roof, which vents the air space above the ceiling and below the roof membrane. They look like this installed on the camper.





The inside looks like this with the top cover off.


I have been researching attic vents for a while to find out the pros and cons of what is available. In years past, attic vents only seemed to show up on high end 4 season campers and some 5th wheels. I have not yet found Sunline travel trailers with them installed by the factory. These attic vents were not that popular across the RV industry years ago. And still today, many new campers do not have them. Attic vents are now starting to show up on some Keystone product line models, and as reported by a fellow Sunline club member, their new Grand Design travel trailer. Not sure which models/series of those brands have them.

What problems are there with the camper attics?

1. High summer heat buildup in the attic is trapped inside.
2. During the right conditions in cool weather, mold can form in the attic from trapped moisture.

Both problems can create problems within the camper, depending on the camping or storage conditions of the camper.

High heat buildup: An example most can relate to is when your car is parked and closed up “tight” all day in the hot summer sun. High heat builds up inside the vehicle beyond the heat absorbed from coming in the window glass. You can feel the heat blast hit you in the face when you open the door as the vehicle does not breathe. The camper has the same heat buildup in the attic as there is no venting of the attic airspace. The attic's high heat eventually migrates to the living space combined with heat coming in the windows. This heat buildup happens when the camper is parked in the sun or long-distance towing down the road on hot summer days. The high heat exposes stored food to elevated temperatures when stored in the camper, and the high heat makes the AC unit work harder, trying to cool the trailer once you are at camp.

Trapped moisture: Small spaces with people living in them during cool months of the year can create high moisture if the living space or attic is not humidity-controlled. High humidity naturally migrates itself to areas of lower humidity. When the living space is stationary (like a parked camper), higher humidity/moisture tends to migrate upwards and into the attic if the moisture cannot get out an easier lower path.

When the outdoor conditions are right, higher moisture collects inside the camper from people living inside, cooking, washing, and sleeping. When you see single pane windows inside the camper sweat, conditions of higher moisture exist. These higher moisture conditions happen during the spring, fall, and winter camping when the windows and roof vents are usually closed, trying to keep the heat inside.

Camper attic findings. Now, close to about two years ago, I restored two campers for friends by replacing the roof on both as part of the project. With the roof off, you could see inside the attic space what excess moisture conditions can create. The larger camper in the project, a 2007 T286SR Sunline, was not used much in the early spring or later fall and had a lower level of moisture signs in the attic. The smaller camper, a 2005 T2363 Sunline, was often used for spring to fall camping, which exhibited signs of a much higher moisture level in the attic. Both campers were bought new by the original owners, so they had the full history. Neither friend knew about the venting needs of a camper for excess moisture and never thought to vent the trailer or control the humidity inside. Their main goal was, try and keep all the heat in you can. Many of the older camper manuals do not mention this higher moisture topic and what to do about it.

After seeing the corrosion of the heads of steel screws and how mold can form in the camper attic, I now have firsthand information on what can happen if the camper's overall moisture is left uncontrolled during these high humidity conditions. This moisture issue is an RV industry problem, not just unique to Sunline. The RV industry knows about attic vents, and the cost is minimal, so why not install them in every camper at the factory? Granted, what you will see is not mega damage, but it is not wanted and can be minimized or eliminated without too much effort.

See these pics from the 2005 T2363 camper, built in August of 2004. I do not have a timeline of when this attic molding issue started. Fifteen years later, after being built, the roof is opened up, and we see this. This mold growth did not all happen at once and may not have occurred during some years.

This camper did have a rear roof corner and front roof seam leak, but there was a strange wet spot in front of the AC unit. The moisture meter showed high 90 percentage readings that “something” was going on in the roof in front of the AC unit. There was no apparent leak path from a roof penetration to this area using the meter scanning from the ceiling inside pointing up and outside on the roof scanning down. The roof was dry near any roof penetrations in that location.

This red circle shows the area in question. High 90 percent on the moisture meter, yet outside that area is 0%.


Here is a picture of the roof before taking up the membrane. You can see there are no holes in the roof in the circle area.


When we rolled up the membrane, I found the wet spot. Water droplets were lying on top of the pink insulation. I felt the insulation with my bare hand, and it was like a fine mist of water was sprayed over all of it. When I lifted the insulation, the water droplets ran off the top. I did not get a picture of that water, but I described what I saw. This wetness was an eye-opener having that much moisture still present when we opened the roof up. It was late October 2018, and the couple camped in a camper only one night before. You can see the blackened stain on the 1/8” luan sheet, which helps hold up the membrane by the AC hole opening.


Here is a picture looking towards the rear of the camper. The insulation is over the top of the rafters. The rubber membrane and the thick corrugate liner nicknamed “bud board,” which I think is a product called Unicore, is directly against the insulation.


Here are some pics with no insulation installed showing molding on every rafter center location and corroding screw heads and speakers in the bedroom.

An overall view looking from the back of the camper to the front


A close up looking forward


An overall view from the roof AC area looking towards the back, see the fuzzing corroding screw heads.




Over the bedroom area





The 2007 T286SR did not have the molding issue, but all the screw heads in the attic over the bedroom area had the same screw head corrosion starting, and you could see moisture stains on the budboard when we rolled up the roof.

This water stain was on the budboard of the rubber membrane where ever there was an opening in the insulation. This water stain is just one example, and there were many others just like it.


And the corroding screw heads over the bedroom area.


The excess moisture vapor in the camper migrates/seeks an area of lower moisture naturally. It rises upward while doing this. The humidity gets up into the attic through any tiny openings in the ceiling of the camper. And there are many of them, such as;
1. Trailers with both ducted and non-ducted AC units have small spaces in the attic's airbox system in the attic.
2. Ducted AC units have small openings in the ceiling air registers in the attic.
3. The shower steam dome area has small openings to the attic.
4. Ceiling radio speakers, the 14 x 14 crank up air vents all have small openings to the attic.
5. The ceiling lights have small wire hole openings to the attic.

There are many openings, and trying to seal them up solid may not be practical. The water vapor keeps rising until it hits the rubber membrane impervious to water and stops there. The vapor cannot get out of the attic. With enough time and quantity of moisture, mold can start to grow on the wettest surfaces. It appears the center of the camper in the rafter area is the place it can begin.

More in the next reply.

For more pics on this topic, see my Flickr photo site here https://www.flickr.com/photos/camper...57717497136833
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Old 12-28-2020, 04:01 PM   #2
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So how do you control the high attic heat and moisture problems?

For the moisture issues, here are some methods I use to help keep it under control. I learned about venting from winter camping with the Scouts in a tent. We knew you have to vent the tent, or else, come morning, the top of your sleeping bag and the whole inside of the tent will have excess moisture buildup inside it. And when it gets down to 10F or below, it may even snow inside the tent from your breathing overnight. Yes, we had a few 16-year-old Scouts prove that concept of snowing inside the tent. By opening a tent door flap a few inches at the top, the problem comes under control. The higher moisture inside the tent is trying to get out to the lower moisture area outside, so with the door flap open a little at the top, you let the excess moisture go where it wants to go, out.

I re-learned the same venting lesson long ago one night when we winter camp in the Sunline. This one night, I forgot to vent the living space, and come morning, the walls were soaking wet, 70% - 75% relative humidity inside the camper. This high humidity can develop in the trailer with two adults sleeping overnight with no venting.

To control camper humidity, I start with a humidity meter with a high/low feature to tell the last 24 hours extremes reached. Knowing the humidity level helps know you have the problem or not. I have used both of these meters, and they work well.

AcuRite 00325 Indoor Thermometer & Hygrometer. See here https://www.amazon.com/AcuRite-00325...s%2C258&sr=8-3

Or here, an AcuRite 00613 https://www.amazon.com/AcuRite-Humid...s%2C258&sr=8-4

To vent the camper, I started out learning how far open to open a roof vent at the opposite end of the trailer from where we slept. I started at about 1/4", and a small amount kept growing to the right size of 1” up to help keep the moisture in check ( 40 – 50% relative humidity). We also use shrink-wrap on the windows to keep the heat in and reduce the sweating windows. When showering, cooking, and washing dishes that create excess moisture, we take extra action steps to lower the humidity in those areas. We open the bathroom ceiling vent about 3” while showering, then close it when done. When cooking or washing dishes, we crack open the window next to the stove and close it when done. We found that venting alone did not keep the moisture down far enough in all condtions, but it immensely helped the problem. Next came running a small dehumidifier, which worked the best. We could keep the camper at 35 – 45% humidity and have the ceiling vents closed. These measures kept the moisture in check, and we camped about eight years of winter camping with the small dehumidifier and the venting practices. Early spring and late fall, we practiced the same methods.

Next came installing attic vents, which started about 1 3/4 years ago. I wanted to get firsthand data on the high heat in the summer, to cool weather camping in the spring/fall to see if I can find the difference made by the attic vents before posting about it.

During the high heat of summer in 2019, we started towing cross-state from OH to PA, up into NY, then VT, and back to Ohio as the first long trip with the attic vents installed. Here are the findings after installing them in our T310SR. Note: The mini blinds are down and fastened when towing to help keep some heat out. The ceiling vents are also closed, with foam cushions installed to keep the sun heat out, which is standard practice for us.

1. For an 8-hour tow, starting early morning, ending mid-afternoon, the camper temperature inside was the same as the ambient outdoor temperature. 85F outdoors, 85 F inside. Before installing the attic vents, outdoor temperatures of 85F would create 95 to 100F inside by the end of an 8-hour tow.

2. For a 4 hour tow, starting mid to late morning, ending mid-afternoon, the camper temperature inside was 5 to 10 F degrees lower than the ambient outdoor temp. 85F outdoors, 75 - 80 F inside. Before installing the attic vents, it was always hotter inside by approximately 5 to 10 F degrees.

3. For a 2 - 3 hour tow, starting late morning to noontime, ending mid-afternoon, the camper temperature inside was 10F lower than the ambient outdoor temperature. 80F outdoors, 70F inside. Before installing the attic vents, it was always the same or approximately 5 F hotter inside.

This pattern above continues to hold for any summer towing. There was a very notable drop in the inside temperature after adding the attic vents. By adding the attic vents, we allowed the trapped high heat in the attic space to vent to the outside either when towing or the camper stored outdoors in the sun.

Cool-weather and humidity. We camped mid-November this year for three nights here in OH. We had the shrink-wrap on the windows and the dehumidifier with us in case we needed it.

Nighttime temps dropped to 35 F the first night and just below freezing, 28F, the other two nights. The days were mid 40’s to 50F. The weather conditions were right to create high moisture in the camper.

The first night, I had the roof vent in the living area my traditional 1” open all night and day and practiced our standard venting for cooking, cleaning, and showering. Just no dehumidifier was running. During the first daytime hours, the humidity in the camper was 35 to 45%. Come the next morning, and still with no dehumidifier running overnight, the inside was at 45% humidity. I was amazed at this and thought it was a fluke or warmer that made a difference during the day.

The second night, I closed the roof vent. Daytime humidity in the camper was 40 to 45%. Come the next morning, and still, with no dehumidifier running overnight, the inside was at 45% - 50% humidity. Wow, OK, this is different.

The third night, the roof vent closed. Daytime humidity in the camper was 35 to 40%; the sun was shining that day. Come the next morning; still, with no dehumidifier running overnight, the inside was at 40% - 45% humidity. OK, the attic vents are doing something positive the pattern is repeating.

I only have three nights to report on the cool weather camping so far. We had many days of summer towing to prove out the lower inside temps than we used to have. At this point, we will still keep the dehumidifier in the camper when we winter camp until I get more data if and when I would need it. I will update this post as future cool weather camping comes.

The attic vents do help. They are not the total cure; you still have to practice good venting habits during high moisture times in the camper.

This post is not intended to have everyone run out and put attic vents in, but to be aware of the need to vent the camper during times of cool weather camping. If you are doing a roof replacement, that is an excellent time to consider adding attic vents. If your camping conditions find that you want to slow down the summer high heat from towing or when the camper is stored, adding attic vents can help.

I will show the install methods for both walk on and non-walk on roofs in the next reply.

Hope this helps

John
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Old 12-28-2020, 05:40 PM   #3
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Hi John,


You and I talked a couple weeks ago about my roof replacement project on the Jayco. I was mystified by the amount of moisture damage because there were no tears or penetrations in the roofing membrane. I thought about attic venting because we do that in houses. A couple of question tho:
1) If I just add a vent to the roof, am I expecting "makeup air" to simply seep through openings around ceiling fittings and what-not? Houses have soffit vents for makeup air.
2) If my "attic" is fully insulated, how could there be adequate air exchange?


I'll be installing a new roof, I'm thinking one (or two?) of these attic vents may be worth doing.


Thanks!
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Old 12-28-2020, 06:36 PM   #4
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Here is how I go about mounting the attic vents in a Sunline budboard rubber roof and a decked roof.

Here is the vent brand I use. A couple of different brands offered; I found this style/brand to be the best. JR Products 02-29125

https://jrproducts.net/product/02-29125/

I bought many of these off of eBay from two different sellers. The pricing varies. JR Products is an RV aftermarket seller of RV parts packaged for them. A molder makes them, and JR sells them. You can find this style on eBay, but you have to look closely that the screen and the segmented parts are the same as the JR brand. Amazon has them too. Since I bought six campers worth of them, I shopped around for the right quality and the better pricing.

Pending the size of the camper, 3 to 4 vents are installed. More on this and why later in the post.

There are two issues I found with all of the brands I tested and corrected before installing. The first correction is the stainless center bolt. The bolt is not captive to the vent. That means the bolt can fall out in the attic if you take the vent apart once it is sealed to the roof. I hot melt glued the head of the bolt to the vent's base to overcome the problem.


Holt melt glued the hex head to the hex molded head socket.


Next, dealing with the Sunline budboard roof, which also applies to a Sunline metal roof. The roof structure does not have any backing to accept screws to hold the vent to the roof. To overcome this, I added 1/2" thick plywood backer boards to install under the roof membrane to accept the screws.

I first tested the 4” hole saw on a scrape leftover piece of Sunline roof to make sure the roof would cut out a clean hole as needed. There can also be 1/8” luan board in the Sunline roof system, so I tested that too. A sharp hole saw will cut clean. Just hang onto the drill motor and go slow. That large bit can grab and twist your wrist if you are not prepared/holding on for it.


Making backer boards, start with laying out an 8” x 8” square (or larger) with a center mark to drill a 4” hole saw a hole in the center. Mark the hole centerlines X and Y across the entire board.


I drill the 4” hole saw before cutting the squares apart, easier to hold the board while drilling.


Cut out the squares, then turn the squares into circles and spit down the center. You are making two halves of a complete circle. Mark which cut-outs go with each. Sand off rough cut edges.


Then sort out where to install them on the roof. Here are the needs, every floor plan and roof rafter layout will alter where they go. The main needs are:

1. One vent to be installed over the bedroom/sleeping attic area. This area is a high moisture area from people breathing overnight.
2. One vent to be installed over the bathroom attic area. This area is to vent the moisture leaks from the shower dome into the attic.
3. One vent to be installed over the kitchen/living room area. This area is to vent the moisture migrating to the attic from cooking/ dishwashing. It also covers the small spaces of the roof AC unit, leaking room moisture into the attic.
4. The vents are ideally mounted “behind” any Maxx air covers, crank up roof vents, AC units. This method creates a wind block when towing in the rain to not force water up into the vent.
5. The vents are to be installed in the open space between the rafters.

Here are a few floor plans showing the above needs.

2007 T286SR. 1 vent over rear bedroom, 1 over the bathroom area, 1 vent over the kitchen/living room area

2005 T2363. 1 vent over the rear bedroom, 1 vent near bathroom/AC unit, 1 vent in the kitchen/living area


2004 T310SR. 1 vent over the front bedroom, 1 vent over the bathroom area, 2 vents over the kitchen living area. This more extended floor plan needed an extra vent, and the rafter spacing behind the AC unit forced one vent back a little.


I install these on the centerline of the camper. And they get installed centered front to back between two rafters. Feel the roof for the rafters on the nominal 16” centers, and back into the middle of the two rafters. Draw center lines on the roof and test-fit the vent before drilling the 4” hole. NOTE: there is “front” to the vent. Note the vent screw locations with the front pointing forwards.


Most rubber roofs have small 1/8” luan sheets at the roof vents to add water drainage support. You will be drilling the rubber/budboard and the luan. Take care not to drop into the attic with the hole saw to grab the insulation.




Test fit the half-circle backer board to get it in the hole and not hit anything, wires, rafters etc. NOTE. The split line of the half-circle backer board to be rotated to not fall into the screw holes of the attic vent.,


Apply construction adhesive to the backer board to bond to the underside of the budboard.


Stick the backer board half in place.


Use a clamp (I used a toggle clamp) and clamp the half you just glued in. Note the backer board split line orientation. Use fender washers and flat head screws to screw in the backer board. Put screws to the backer board inside the vent outline circle when one half is screwed in place, glue-in, and screw in the second half.


Clean the roof surface with a high flash cleaner to get any dirt off. This rubber must be clean and dry. I use Naphtha as a cleaner. You can use denatured alcohol, isopropanol rubbing alcohol, or lacquer thinner. Wipe cleaner with a rag, do not soak rubber with cleaner.

Apply butyl sealing tape to the bottom of the vent mounting flange. Leave the release paper still on. Remove the top cover by unscrewing it from the vent. Take the nut off the center bolt and remove the top deflector shield. This will allow more room to get to the screws. Note: This is why I hot-melt glued the hex bolt to stay captive, or it would fall out into the attic.


Remove the butyl release paper, heat gun warm the butyl.


Align the screw holes to the center lines and press vent to roof. You can use a drill driver to get screws started, do not use the drill to tighten, hand tightened. I use no. 8 stainless screws and fender washers to help spread the compression load out on the plastic flange. Trim excess butyl.


Place top shield on and tighten the center nut. Orient the front of the shield to the front of the camper. Next, we will measure the dome cover for a lock screw. 2 3/8” is where we will drill a hole in the cover “once” the cover is tight.


Screw the cover onto the vent. Hand tighten the cover on the center bolt, do not over tighten. Find the center of the cover and draw a line up the centerline of the camper. Measure 2 3/8” from the center and put a cross mark to drill a hole. This will be for a screw cover lock screw.


Using an1/8” drill bit, hold the bottom of the vent shield, spread your fingers so you do not drill them, and drill the top cover and the shield straight down through both. Go slow to not over poke through the vent shield.


Using a no. 8 x 1 1/2" long stainless screw, hold the vent shield and by hand, screw the screw through the cover and the shield. You will cut threads in the plastic of both parts as you screw it on.




You can now remove the screw, the nut, and the top shield. Clean the vent flash and apply Dicor self leveling lap sealant over the flange screws and outer flange.


Assemble the vent shield, the cover, and the lock screw. Apply a dab of Dicor over the top of the screw head. A soapy water finger will allow you to flatten the wet Dicor and not have it stick to you.


If you use Eternabond, wait 3 weeks to 1 month to allow Dicor to gas off and cure. Then apply Etnernabond.


The reason I added the lock screw, online reports are folks reporting the domes unscrew themselves over time, and they have to buy the entire vent to get the cover to replace it. In my mind, the cover vibrating off is problem one. I came up with the lock screw to prevent the cover from loosening, but yet you can get it off if needed.

If you have a thick enough deck board, you do not need to make the half-circle backer boards. Or if doing a new roof that is thin, add backer boards as needed before screwing the deck down.

Hope this helps,

John

For more pics on this attic vent topic, see my Flickr page https://www.flickr.com/photos/camper...57717497136833
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Old 12-28-2020, 06:58 PM   #5
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Hi Chuck,

Some answers to your questions.

Quote:
Originally Posted by JaycoJake06 View Post

snip..

I was mystified by the amount of moisture damage because there were no tears or penetrations in the roofing membrane.

I thought about attic venting because we do that in houses. A couple of question tho:

1) If I just add a vent to the roof, am I expecting "makeup air" to simply seep through openings around ceiling fittings and what-not? Houses have soffit vents for makeup air.

2) If my "attic" is fully insulated, how could there be adequate air exchange?


I'll be installing a new roof, I'm thinking one (or two?) of these attic vents may be worth doing.
1. The attic vents allow moisture and excess heat pressure/build to get out of the camper attic. It is a "step" in solving the attic issues. The camper is not built to allow soffit venting like a house, but at least creating a path for the heat & moisture to escape is a really good start. For the moisture, the only fresh air intake is all the tiny holes and crevice's moisture leaks its way up there. I know that amount of air intake is a fraction of the fresh air a house gets, but from my testing, these attic vents do help. The rubber membrane seals the attic up so tight, nothing can get out. The wet just sits and rots the camper.

We see this a lot in restoring camper. If you ever get a roof leak, and you actually caulk the leak shut, the trapped wet insulation will never dry out in a reasonable time as the attic has no escape for the moisture to get out.

My Sons camper had a front leak in the roof. The prior owner caulked it, it looks like a year earlier before trading it to a dealer. His did dry out in the front, as they stopped the leak, but have no idea how long that took. I'm guessing a year of more after the leak stopped. Dry rot then took out a rafter where the water puddled. If that could of dried out in a few weeks, a lot less damage would of happened.

2. The insulation, yes the wet sock up there... the water vapor that leaks up the cracks in the ceiling and any permeation through the ceiling board (very little) does find it's way up through the insulation. Any hole in the insulation left by the assembly crew is an easy path, in the tight areas, it takes longer, but it does work it's way to the top. If I did not feel the dripping wet insulation on the 2005 camper I mentioned above, I would not have believed that, but it did.

I fully agree, add 3 of these attic vents to your camper when you put the new roof on. The last post on how I do it, shows the placement needs.

I feel after learning all this, every camper should have these installed from the factory. It is not much effort at the factory level to do this.

Hope this helps and ask away any questions.

John
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Old 12-29-2020, 08:51 PM   #6
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John, I know every model from Grand Design have the vents.
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Old 12-29-2020, 11:27 PM   #7
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Quote:
Originally Posted by 264SRinPA View Post
John, I know every model from Grand Design have the vents.
Thanks Mike, good to know. How many does your camper have and where are they located?
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Old 12-31-2020, 03:29 PM   #8
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Awesome detail post as usual. I want them!!
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Old 01-08-2021, 10:17 AM   #9
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Great post with stats to encourage this adaption to our T1950. The tent stories brought back some memories, which have encouraged us to use venting techniques so very well described.

We are the second owners of our 21 year old unit, it's been ours 3 years and was pristine! We use a very small electric dehumidifier when we have shore power and I have been amazed this winter at the small amounts collected when unoccupied. Bought that after finding windows wet inside during cold weather. Have since bubble wrapped a few of the windows, easy off/on.

We do keep a oil heater on 600wt during our E. TN winters, it's worth it to us. Sunline is right out our side door and a retreat. There are few months of the year we don't get to camp. Looks like a worthy project even before any new membrane! I wonder that 2 would be sufficient, we don't shower inside. Thank you John!!
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Old 01-08-2021, 10:53 PM   #10
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Originally Posted by Stubborn1 View Post
Looks like a worthy project even before any new membrane! I wonder that 2 would be sufficient, we don't shower inside.
Hi Stubborn,

The oil filled heaters, yes we have one too for the camper. No noise, safe and you still get the heat from it. Ours looks like an old fashion cast iron stand up radiator.

Yes, adding the attic vents before a re-roof can be worthwhile gaining the benefits in summer and cool weather times makes it worth the effort. When a new roof times comes, there are coating systems that can be done to extend the original roof. I am testing one of those newer high solids silicone treatments now. If you do a coating, then the vents can stay. And if you go the re-roof route, the cost of the attic vents that would be tore off is not that large compared to the gain of the features.

On how many vents in a T1950, I just added the attic vent bases to my 2004 T1950 project camper. I picked 3 of them for that floor plan. See the pics here on the placement.

The 4" holes in the decking before the new rubber went on,


The attic vents bases installed over the new membrane.








The reasoning behind why I placed them in those areas.

1. The front living room area. This vent allows the entire front of the camper attic to be vented. Excess heat leaves in the summer for this whole area. The moisture generation is lower in this section, but the roof AC unit hole allows kitchen moisture into the attic and this front vent allow it to escape from the front section.

2. Behind the roof AC unit. This location is based on the kitchen area moisture generated from cooking, washing dishes. If lets the summer heat out of the middle of the attic and is close to high area in the camper of moisture generation. The AC unit is in this section and the hole in the ceiling for the AC allows moisture into the attic.

3. Over the rear bedroom. Two adults sleeping at night creates a lot of moisture. The bedroom area is a high moisture generator. It also lets the heat out of the attic in the back of the camper in the summer. With the T1950 floor plan, there is no attic vent in the bathroom, it is so small. There is a crank open ceiling vent that can be opened to let shower steam get out of this space. With the bathroom so small, it is really is not practical to add an attic vent in bathroom with this floorplan.

By going with three attic vents, it makes it easier for the moisture to escape. With only two vents, it would be one in the back and one in the front. That distance even though it is a short camper, is pretty long for moisture collected in the center to get out.

That was my reasoning. Two attic vents is hands down better then none and it would for sure help. I just have no data to show that it would be good enough. Adding the third vent made my whole thought process all fit better.

Hope this helps and let us know how this comes out for you if you add them. You might even hold the title of being the 6th Sunline to have attic vents! . There are 5 others as of right now that I know of.

John
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Old 01-09-2021, 01:09 PM   #11
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Thank you for the response, much appreciated. The pictures of your T1950 roof vent spacing do show how much more beneficial 3 would be. It was those bedroom windows that sweat in winter. Well done! Interested to see how the silicone material works out!
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