Roof insulation

[Manie B]

Gents this is a question for the old salts out there

Cabin top insulation against the sun, how important is this,
when you are out there in the middle of nowhere and the sun is beating down
even if you have reasonable ventilation, wouldn't it be better to have say 50mm = 2 inches of polystyrene sandwiched between two layers of ply and glass

So how good or bad would just a single skin of 9mm (3/8") plywood with a layer of glass over it painted a light colour be.

The Beneteau i sailed on was old and the roof lining sh1t and loose, so i couldn't really tell. Just worried that my micro becomes an oven inside on a bright sunny day.

[masalai]

Wear sunglasses, a hat and long sleeved white shirt, paint the roof white (do not even consider a light gray) and does not need to be 50mm I would guess at as little as 10mm or less would be effective, but better still some cloth sheet that could be supported by the stays on those windless days in conjunction with some carefully placed hatches to admit the breezes when desired...

[apex1]

Hi Manie,

I am planning some PV panels to provide shade. Distance will be around 30 to 40 mm to have a sufficient airflow underneath.
Should lower the inside temp by min. 10°C.

edit:
on top of insulated roof, of course.

Regards
Richard

[PAR]

Most of my small boat design incorporate a foam cored roof panel. It makes a big difference in both warm (my climate) or cold areas. A 6 mm plywood skin over 25 mm of foam with a 6 mm plywood inner skin, makes a strong roof, with little need for hanging beams to smack your head on., It's also lighter then plank over beam and is made water tight with the sheathing.

[Manie B]

Thanks PAR

A 6 mm plywood skin over 25 mm of foam with a 6 mm plywood inner skin, makes a strong roof

this is exactly what i had in mind
just very nice to know that i am not re-inventing the wheel
and that it comes from experience :cool:

[SamSam]

Most of my small boat design incorporate a foam cored roof panel. It makes a big difference in both warm (my climate) or cold areas. A 6 mm plywood skin over 25 mm of foam with a 6 mm plywood inner skin, makes a strong roof, with little need for hanging beams to smack your head on., It's also lighter then plank over beam and is made water tight with the sheathing.
Would this have internal beams? How big an area would this span and how much load would it support? Have you ever tried this for cabin walls?

[PAR]

You can span as big an area as you'll find on most small yacht roofs. You can use internal beams if you like, depending on crown size and distances involved, etc. I generally "edge" the perimeter with milled 2 by stock and any opening to offer a finished edge and something to drive a fastener into, but no internal beams per say unless the crown is slight. No, I haven't used this for cabin walls, as it's more effort then necessary, when a piece of plywood or solid limber will do just fine. I don't like to make things any more complicated then necessary, though if I was doing a severe service craft, where I could justify the extra bother, cabin walls could be made this way. Of course sheathings in this type of craft would be just as important as the cored wall.

[SamSam]

I was thinking of it for walls of a house boat. It's like the insulated structural panels used in timber frame houses. When that was a new idea for enclosing timber frames there weren't many manufacturers of the panels and one writer tells of the local lumberyard making them. A sheet of ply was rolled with glue, a piece of foam layed on that and rolled with glue and another sheet of ply then layed on the foam. Then another set of ply/foam/ply etc. until the pile got too high to easily work on. A layer of cement blocks was then put on and that pile was left to set up and another pile started. This was done by high school kids after school.

The structural panels in timber framing have evolved over the years to being a structure in itself, with no need of any frame to support them, and large structures can be assembled in a day that usually take weeks.

In some situations it might be less bother to assemble a large panel on a work surface and then put it in place instead of assembling it in place piece by piece. In the ply/foam/ply roof panels you've made, what kind of foam and what kind of "glue" did you use, and did you use any clamps or pressure? Thanks.

[boat fan]

Blue Foam for house construction can be used.

You could use construction glue , but epoxy would be much better.
The 40 mm panels , when sandwiched between plywood , gives a much stiffer panel than the 20 mm on the same camber.



STYROFOAM™ LB

STYROFOAM™ IB Insulation improves the thermal performance of existing walls without affecting the appearance of the building. The insulation is lightweight and easy to cut, making it suitable for use around existing details. STYROFOAM LB Insulation can be adhered to or mechanically fixed to the existing walls. 　 Board Size(length x width, mm) 2500 x 600, 2500 x 1200 Thickness (mm) 20, 40, 60, 80, 100, 120 Edge Treatment Butt edge Surface Planed

Don`t use polystyrene.

[SamSam]

Most of my small boat design incorporate a foam cored roof panel. It makes a big difference in both warm (my climate) or cold areas. A 6 mm plywood skin over 25 mm of foam with a 6 mm plywood inner skin, makes a strong roof, with little need for hanging beams to smack your head on., It's also lighter then plank over beam and is made water tight with the sheathing.
In the ply/foam/ply roof panels you've made, what kind of foam and what kind of "glue" did you use, and did you use any clamps or pressure? Thanks.

[PAR]

SamSam, the structural panels that are used in land based roof systems and timber framing now are pretty highly engineered products, which also requires a "system" of attachment and stabilization. You'd be well advised to hire the loading out to a designer, which would be a small portion of the total build effort.

My panels use epoxy and 4 pound polyurethane foam and have perimeter solid wood elements as well as carlins for all openings. If the carlins are load bearing, then they are tied to the perimeter elements with stringers. It's the exact same engineering rules, used in the structural panels employed in land based systems. Don't kid yourself about how much engineering goes into these seemly simple panels.

[mydauphin]

I bought a infrared thermometer and measured three parts of hull all next to each other in direct sunlight, black, grey and white. Huge difference. Put a piece of astroturf on top, even bigger difference. So paint it white and put something over it, tarp, rug or some canvas.

[PAR]

Separation is what you need, which is one reason the foam panel is what I employ in my designs. Thermal isolation is what you need and this construction method works quite well at it.

[boat fan]

SamSam, the structural panels that are used in land based roof systems and timber framing now are pretty highly engineered products, which also requires a "system" of attachment and stabilization. You'd be well advised to hire the loading out to a designer, which would be a small portion of the total build effort.

My panels use epoxy and 4 pound polyurethane foam and have perimeter solid wood elements as well as carlins for all openings. If the carlins are load bearing, then they are tied to the perimeter elements with stringers. It's the exact same engineering rules, used in the structural panels employed in land based systems. Don't kid yourself about how much engineering goes into these seemly simple panels.


Actually PAR , in the 18 plus years I have spent in the building industry , I have yet to see a panel system that is regularly used that is highly engineered for high loading.

The industry is a rather conservative bunch and don`t take to change too readily.

Speed of construction has improved significantly , but , at least in the domestic sector that I work in ,all systems now commonly used still rely on the conventional premise that paneling is fixed to , or hung off skeletal
framing or sub - framing.Just as it has been for decades , in fact more than a century.

Here in Australia and in Europe ,the framework spacing supporting the panels is standardized , usually in 300 mm increments so spans are usually in sums of 300 , 600 ( studs ), 900 , 1200 etc mm centres. Small spans that are well understood , and hence - not a lot of engineering required. Ditto for roofing. Flooring often 450 mm centres.

More attention is directed at the loadings of the supporting structures , i.e. framework , and the method of fixing the panels.After the horrendous Darwin cyclone on christmas day in 1974 the codes were re - written and changes were made to anchoring systems , particularly upper and lower wall plates,and associated perimeter tie - downs. Not the panels.

All wall panels used here today are regarded as cyclone safe but not all the methods of fixing .If best practice is followed , it is sufficient for walls on house boat construction.Once again it is the framing and / or sub framing that carries the loads on a house boats ,as they are built here , roofing align with wall framing ( studs ) etc....again 300mm c , floors are engineered to resist excessive torque etc. engineering will be required there , and while panels help with bracing by their nature, panels for house boat construction , at least here , is nothing special.

[PAR]

I agree that most industries are slow to adopt new methods, techniques and materials, with construction well known to it's slowness of evolution.

Just because the current use of land based SIP's has yet to take advantage of higher levels of engineering possible with the method, doesn't mean it's not occurring. It just means as you've pointed out that they're slow on the up take. This is the usual course. It took nearly a half a century for plywood and other sheet goods to fully catch on.

SIP's used over framing is a safe way to introduce folks to the idea of something new. It doesn't use the panels to full effect, but does get them on site and change building patterns.

On the other hand, I've seen modular buildings go fully seal up in 3 days, using a fully integrated SIP's based system. The walls are built off site, under climate control conditions, with everything in place. A crane spends a day or two erecting panels, then the finished doors and windows are slapped in, sealing the building. I watched a friends 2,000 sq. ft. two story garage go up in 2 days this way. On the third day the roof was skinned with shingles and the siding went on. The whole project, from start to finish was a week, paint, plumbing and flower boxes. So, it's actually being done, just not as much as hanging them on conventional frame works.

With some modest engineering (http://www.sips.org/elements/uploads/fckeditor/file/SIP%20Engineered%20Design%20Guide.pdf) you can save about 30% in dimensional lumber. With the curved roof panels I designed and was discussing in this thread, the solid lumber savings is more on the order of 60%, of course these are more highly engineered structures.

You can take this to the next logical step, which eliminates most of the dimensional lumber requirements, but now you have to get the industry to bite into goo's and monocoque structures, which is more then pulling teeth to say the least. Maybe by then, we'll have moved into the era of high modulus polyesters and resins that remove the need for wooden sheet goods all together. Wooden platform frame construction will be considered "quaint" and inefficient, with the wife complaining about the stairs creaking as she walks up them. You and I will be long dead, but it's coming.

[boat fan]

You can take this to the next logical step, which eliminates most of the dimensional lumber requirements, but now you have to get the industry to bite into goo's and monocoque structures, which is more then pulling teeth to say the least. Maybe by then, we'll have moved into the era of high modulus polyesters and resins that remove the need for wooden sheet goods all together. Wooden platform frame construction will be considered "quaint" and inefficient, with the wife complaining about the stairs creaking as she walks up them. You and I will be long dead, but it's coming. http://www.boatdesign.net/forums/images/buttons/quote.gif (http://www.boatdesign.net/forums/newreply.php?do=newreply&p=316422)


At the very least retired PAR ,:D


Here`s an interesting angle on modular :Interview: Ruhl Walker Architects Talk Shop with the Empyrean Design Partnership
( builders )

-[/B] light fixtures and structure were not coordinated or aligned, for instance.

There are some risks with modular that I hadn’t thought about before, like how it an entire house can go up in three days. But that scares clients, too. One day there’s nothing, and the next day there’s a whole house. Since the clients don’t know what to expect, all of a sudden there’s a house and it’s too late to make any changes. With panelization, if you’re working with clients who want to make a change on the fly, it’s a lot easier to do, obviously.[/B]
:D :D :D

Brad Walker: I certainly wish there was a way, using panelization, whatever the next layers of evolution are, to get more and more done in the factory. Interior finishes, which are labor intensive, and the part you see all the time and therefore in need of precise craftsmanship, are done on site in your system. It would be great to be able to do that in the factory.



I hope it will happen sooner rather than later myself......will cost some jobs though.....

[apex1]

Ui ui ui...

where are you living?

Will Ruhl: There are some risks with modular that I hadn’t thought about before, like how it an entire house can go up in three days. But that scares clients, too. One day there’s nothing, and the next day there’s a whole house. Since the clients don’t know what to expect, all of a sudden there’s a house and it’s too late to make any changes. With panelization, if you’re working with clients who want to make a change on the fly, it’s a lot easier to do, obviously.

That is standard in W Europe since more than 50 years now.
And it did not cost any jobs, they just work under a roof now.

[boat fan]

Ui ui ui...

where are you living?



That is standard in W Europe since more than 50 years now.
And it did not cost any jobs, they just work under a roof now.

That quote was from Ruhl Walker Architects in BOSTON, MA USA.

As things stand now, here in Australia most housing is produced on site.

I think it would cost jobs here Richard , because prefab housing
utilizes a higher degree of automation during production.
This is a country with just 22.5 million people , there would only be room for a select few big operators.
Exporting would not be viable from here , distances would prevent access to overseas markets , high transport costs would see to that.

All the on site crews would be gone .
You could probably argue that point for ever , as it is difficult to quantify accurately.

[PAR]

A small percentage of jobs have and will be lost to modular building methods. Platform framing also cost jobs over balloon framing, plywood cost jobs over double diagonal, electric saws and other tools cost jobs, the whining goes on, but it's typical of progress. We as a species don't have to climb trees to gather food any more, putting long armed brothers out work (maybe they should have had a union) too.

As ACad work progresses the bugs will get ironed out, and they have on the high end stuff. Start to finish "walk throughs" charge backs and change orders included before the panels hit the site have been preformed with flawless precision. Of course the other end is true as well, where the contractor is on the site with a chain saw cutting in new doors and windows. This all will be sorted out and yes, some jobs will be lost, but entire industries will open up and others will evolve. Robots were going to replace the auto worker and steam powered track laying machines where going to replace the railroad laborer, the same old song of the squinted eye, well entrenched non-visionary, which includes architects that aren't interested in learning new formulas, systems and methods to do a job "that worked just fine" the old way.

[boat fan]

Like I said before PAR ,I hope it will happen sooner rather than later myself....

[Fanie]

Manie,

Why don't you just use the PE foam on your roof. Remember you get it in various colours, so you can make it attractive as well when you walk on your boats walls :D

You can glue it in place with Sikaflex or Dow Corning. Any of those adhesives will work fine.

[apex1]

That quote was from Ruhl Walker Architects in BOSTON, MA USA.
I know and included the name in the quote.
As things stand now, here in Australia most housing is produced on site.

I think it would cost jobs here Richard , because prefab housing
utilizes a higher degree of automation during production.

You could probably argue that point for ever , as it is difficult to quantify accurately.

Have no reason to argue that forever. But fact is, that the automated part of the prefab. is´nt so much, and that our construction business has soon found out, that ALL the skilled labour still is involved. Even the brick layers have´nt lost their jobs, many of those prefab. houses are still clad in bricks!

Looking at the facts one should bear in mind, that the standard (regulations and tradition), to which our houses are built, either way, is so unbelievable high that there is no price difference also.

Regards
Richard

[boat fan]

Bricks !!!!!!......................now there is an outdated way of building a house !

Energy intensive to produce.
Energy intensive to transport
Energy intensive to erect.
Anything remotely connected to cement is also.
Slow........OUTDATED .....:D.....TERRIBLE !!!!:D

It`s not really surprising , nor co- incidence that the most advanced prefab. construction methods are being developed in the Northern Hemisphere , given
that this part of the world experiences the harsh winters not favorable to on site construction.Your building standards are high , no doubt about it Richard.
It`s a product of a well developed , mature and established industry in your part ( EUROPE ) of the world.

It`s also not surprising that it has lagged behind in Australia , as we don`t have " winters" in that sense. No need to go indoors.



What my original point about all this was , it`s not necessary to go to highly engineered panels and their associated expense to clad / skin / insulate / roof a house boat.


Too far off topic now , so I will now be quiet on that topic .:D

[apex1]

Me tooo

[SamSam]

Actually PAR , in the 18 plus years I have spent in the building industry , I have yet to see a panel system that is regularly used that is highly engineered for high loading.


Speed of construction has improved significantly , but , at least in the domestic sector that I work in ,all systems now commonly used still rely on the conventional premise that paneling is fixed to , or hung off skeletal
framing or sub - framing.Just as it has been for decades , in fact more than a century.

In one of TedBenson's timberframing books he has a chapter or two devoted to the history of SIPs and in one (1980-or 90s) there was photos and a short description of a motel being put up where the wall panels supported the roof trusses. You could be right in that studs might have been incorporated into the panel, I don't remember. The whole thing was assembled in a day, the panels camlocked together almost as fast as they could be unloaded from the truck.

I am kind of interested in something where a wall panel and a roof panel of the length needed could be built under cover, horizontilly,on a flat surface, where gravity would be your friend and bad weather might be considered pleasant, and then be put in place. I would also want a wall and roof system where you could utilize the roof for porch like purposes, walking, sitting, eating etc. It would have to be "ciphered" or designed using interior components like bulkheads, walls, cabinets, maybe a beam or two as structure, but it would seem to be light, strong, insulated etc.

[boat fan]

That can most certainly be done Sam , I don`t see any problem there.

I`m not familiar with the example in the Ted Benson book , and the panels referred to may or may not have framing integrated within them , but I do know without any doubt , that the way we build today , here and now , SIP does not feature to any significant degree.

I think you could produce panels like that by laminating.
Roof panels could be laminated with foam / glass , or foam / kevlar ( costly ) or foam /ply even ,
over a simple cambered mold. It would not be too difficult or costly to produce some test panels .
Edges can be rebated like t & g flooring .Channel capping (similar to the way fences are built here) , can slip over the wall panel edges ,( mostly self aligning) and use of non - ferrous tek fasteners would ensure fast assembly.

Personally I would like to see more of it if the cost is contained.