??? about fiberglass roofing a houseboat

If it just small cracks then laying down more cloth is probably
overkill. I'm going through the same kind of exersize after
removing my teak decks. If the old surface is gelcoat, then
laying cloth over it is a bad idea. The gelcoat will have to be
removed to get to the existing glass. The secondary bond
characterists of resins over gelcoat is not good. The
solution that I am using is applying 2 coats of epoxy barrier,
then a 2-part polyurethane finish.

Doug
s/v Callista

<dh_ld DeleteThis @nomail.com> wrote in message
news:qtbah0pqjavkfa6mmquo2be654grcme5ee@4ax.com...
 > I have a houseboat whose roof has a bunch of thin
 > spider cracks, as well as some a bit bigger. The
 > biggest ones aren't wide enough to get any more than
 > a razor knife blade in, if that. I want to put some more
 > fiberglass sheet on it, and have never done that before.
 > Having talked to several people about it, the following
 > is pretty much the impression I've developed about
 > doing the job, and I'd appreciate any more suggestions
 > or advice people are willing to share:
 >
 > · First, use something like a thin wheel on a grinder and
 > dig out the larger cracks, then fill them in with rosin to
 > make them strong...if that's not done before sanding,
 > the cracks will fill up with dust and never get strength
 > from rosin entering them.
 >
 > · Sand the area with medium grit sandpaper.
 >
 > · Clean area with acetone.
 >
 > · Cut fiberglass cloth to fit the area, then staple in place.
 >
 > · Saturate the cloth with rosin using a roller. Best to set
 > up a cover like a tarp, because in direct sun the rosin
 > could set up too quick.
 >
 > · After all that has been done and dries, apply gel coat
 > ...I've heard to apply 1, 2 and 3 coats, so as yet don't
 > have a good idea of how many to apply.
 >
 > One of the things I'm still trying to figure out, is how to
 > deal with the excess rosin which will want to drip down
 > the side of the boat. Can anyone suggest any good way(s)
 > of dealing with that issue?
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: ??? about fiberglass roofing a houseboat 

On Sun, 08 Aug 2004 19:57:36 +1000, "K. Smith" <ksmith1.RemoveThis@msn.com> wrote:

 >dh_ld@nomail.com wrote:
  >> I have a houseboat whose roof has a bunch of thin
  >> spider cracks, as well as some a bit bigger. The
  >> biggest ones aren't wide enough to get any more than
  >> a razor knife blade in, if that. I want to put some more
  >> fiberglass sheet on it, and have never done that before.
  >> Having talked to several people about it, the following
  >> is pretty much the impression I've developed about
  >> doing the job, and I'd appreciate any more suggestions
  >> or advice people are willing to share:
  >>
  >> · First, use something like a thin wheel on a grinder and
  >> dig out the larger cracks, then fill them in with rosin to
  >> make them strong...if that's not done before sanding,
  >> the cracks will fill up with dust and never get strength
  >> from rosin entering them.
  >>
  > Resin itself has very little strength so if you choose to fill the
 >cracks first add some filler to the resin, say Q cells & make a paste
 >(before you catalyse), although a layer of glass over the top should
 >mean you don't really need to "fill" suck small cracks first.

Thanks for the input! By now I've changed my plan somewhat.
At this point I intend to fill the cracks with a filler material recommended
by a guy who does a lot of this stuff, and works at Boater's World. That's
in case water gets between the original roof and what gets added to it,
and also to help hold it over through winter in case I don't get around
to completing the job until spring.

  >> · Sand the area with medium grit sandpaper.
  >>
  >> · Clean area with acetone.

That plan has changed too, and now I intend to add 1/4" plywood
for that much extra strength, before doing the fiberglass. That could
change too though... The original plywood idea was to save a bunch
of sanding and acetoning of the original roof, and also add some
strength. Then a couple of people told me that I need to use marine
grade plywood. The expence of fiberglass and resin was significant,
but now the cost of the plywood would become the biggest expence
....more than doubling the cost of the job. So now I'm left to wonder
how much stronger, better, longer lasting would the plywood be to
the project?

  >> · Cut fiberglass cloth to fit the area, then staple in place.
 >
  > Usually you paint resin onto the surface, then put the glass on, then
 >use a metal roller to pull the resin up through the glass this stops
 >bubbles being trapped under the glass (still use staples if you need to
 >but into the wet glass) & by working the roller with the wet resin you
 >give the binders in the chopped strand glass mat time to dissolve. So
 >it's always best to put the resin on first (not too much) then lay the
 >glass into it.

Thanks. That's pretty much what everyone else has said.

  >> · Saturate the cloth with rosin using a roller. Best to set
  >> up a cover like a tarp, because in direct sun the rosin
  >> could set up too quick.
 >
  > Always do a test bit to ensure the amount of catalyst you'll be adding
 >will give you a gel time of 20 to 40 mins, save there's a dramatic
 >weather change you can then maintain your gel time with confidence.

I've been told to use between 1% and 2%, and also not to use less
than 2%, so still don't know quite how to think about that one. I do
intend to rig a tarp to cover the work area, so the sun doesn't make
things set up too quick.

 >When
 >working do small areas at
 > a time.
 >
  >>
  >> · After all that has been done and dries, apply gel coat
  >> ...I've heard to apply 1, 2 and 3 coats, so as yet don't
  >> have a good idea of how many to apply.
 >
  > Just resin with glass sets very porous. The gel coat is what makes it
 >water tight.

I have had various advice about that one. Most of it has been that there's
no real need to use gel coat, but that any type of marine paint would work
okay. One guy said he used gel coat, but it was too slippery so he went
over it with Elastomeric....here at this marina most people suggest using
that. The two people I talked to that do a lot of fiberglassing said just painting
it would do, and both acted like it really doesn't matter what type paint. One
of those guys did suggest using marine acrylic paint, and adding a bit of a
sandy substance they sell to give the surface more texture.

 >With gel coat one good application should be OK, it's
 >pretty thick stuff but don't skimp, however "normal" gelcoat will leave
 >a sticky tacky surface, so tell your supplier that you need some "wax in
 >styrene" to add to it (about 1%) the wax will float to the top & seal
 >the curing gelcoat from air allowing it to cure right through not
 >leaving a sticky surface.

Thanks. I'll ask around about that at the supply places.

 >If it's a tricky surface (doesn't sound like
 >it) you can spray some PVA over normal freshly applied gel coat to
 >achieve the same outcome.
 >
  >>
  >> One of the things I'm still trying to figure out, is how to
  >> deal with the excess rosin which will want to drip down
  >> the side of the boat. Can anyone suggest any good way(s)
  >> of dealing with that issue?
  >>
 >
  > Masking tape & throw away placky drip sheets from a paint shop etc. If
 >you have a situation which doesn't allow, you can spray PVA over the
 >lower surfaces (it's cheap mould release agent which sets quickly into a
 >placky film) then when finished the drips etc will come away easily, the
 >PVA is water soluble so can just be harmlessly washed off.
 >
 >K<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: ??? about fiberglass roofing a houseboat 

You do not need Marine Ply. The difference in Marine ply and normal outdoor
ply, is the marine ply will have no interior voids. All the plys are
patched before bonding. No voids is good in a transom, with a big motor
trying to flex the ply. For normal walking surfaces, a standard ACX with
waterproof glue is fine.
Bill

<dh_ld RemoveThis @nomail.com> wrote in message
news:3f0qh0t6v92d6dejfc5pcpmkg5cquif98r@4ax.com...
 > On Sun, 08 Aug 2004 19:57:36 +1000, "K. Smith" <ksmith1 RemoveThis @msn.com> wrote:
 >
  > >dh_ld@nomail.com wrote:
   > >> I have a houseboat whose roof has a bunch of thin
   > >> spider cracks, as well as some a bit bigger. The
   > >> biggest ones aren't wide enough to get any more than
   > >> a razor knife blade in, if that. I want to put some more
   > >> fiberglass sheet on it, and have never done that before.
   > >> Having talked to several people about it, the following
   > >> is pretty much the impression I've developed about
   > >> doing the job, and I'd appreciate any more suggestions
   > >> or advice people are willing to share:
   > >>
   > >> · First, use something like a thin wheel on a grinder and
   > >> dig out the larger cracks, then fill them in with rosin to
   > >> make them strong...if that's not done before sanding,
   > >> the cracks will fill up with dust and never get strength
   > >> from rosin entering them.
   > >>
  > > Resin itself has very little strength so if you choose to fill the
  > >cracks first add some filler to the resin, say Q cells & make a paste
  > >(before you catalyse), although a layer of glass over the top should
  > >mean you don't really need to "fill" suck small cracks first.
 >
 > Thanks for the input! By now I've changed my plan somewhat.
 > At this point I intend to fill the cracks with a filler material
recommended
 > by a guy who does a lot of this stuff, and works at Boater's World. That's
 > in case water gets between the original roof and what gets added to it,
 > and also to help hold it over through winter in case I don't get around
 > to completing the job until spring.
 >
   > >> · Sand the area with medium grit sandpaper.
   > >>
   > >> · Clean area with acetone.
 >
 > That plan has changed too, and now I intend to add 1/4" plywood
 > for that much extra strength, before doing the fiberglass. That could
 > change too though... The original plywood idea was to save a bunch
 > of sanding and acetoning of the original roof, and also add some
 > strength. Then a couple of people told me that I need to use marine
 > grade plywood. The expence of fiberglass and resin was significant,
 > but now the cost of the plywood would become the biggest expence
 > ...more than doubling the cost of the job. So now I'm left to wonder
 > how much stronger, better, longer lasting would the plywood be to
 > the project?
 >
   > >> · Cut fiberglass cloth to fit the area, then staple in place.
  > >
  > > Usually you paint resin onto the surface, then put the glass on, then
  > >use a metal roller to pull the resin up through the glass this stops
  > >bubbles being trapped under the glass (still use staples if you need to
  > >but into the wet glass) & by working the roller with the wet resin you
  > >give the binders in the chopped strand glass mat time to dissolve. So
  > >it's always best to put the resin on first (not too much) then lay the
  > >glass into it.
 >
 > Thanks. That's pretty much what everyone else has said.
 >
   > >> · Saturate the cloth with rosin using a roller. Best to set
   > >> up a cover like a tarp, because in direct sun the rosin
   > >> could set up too quick.
  > >
  > > Always do a test bit to ensure the amount of catalyst you'll be adding
  > >will give you a gel time of 20 to 40 mins, save there's a dramatic
  > >weather change you can then maintain your gel time with confidence.
 >
 > I've been told to use between 1% and 2%, and also not to use less
 > than 2%, so still don't know quite how to think about that one. I do
 > intend to rig a tarp to cover the work area, so the sun doesn't make
 > things set up too quick.
 >
  > >When
  > >working do small areas at
  > > a time.
  > >
   > >>
   > >> · After all that has been done and dries, apply gel coat
   > >> ...I've heard to apply 1, 2 and 3 coats, so as yet don't
   > >> have a good idea of how many to apply.
  > >
  > > Just resin with glass sets very porous. The gel coat is what makes it
  > >water tight.
 >
 > I have had various advice about that one. Most of it has been that
there's
 > no real need to use gel coat, but that any type of marine paint would work
 > okay. One guy said he used gel coat, but it was too slippery so he went
 > over it with Elastomeric....here at this marina most people suggest using
 > that. The two people I talked to that do a lot of fiberglassing said just
painting
 > it would do, and both acted like it really doesn't matter what type paint.
One
 > of those guys did suggest using marine acrylic paint, and adding a bit of
a
 > sandy substance they sell to give the surface more texture.
 >
  > >With gel coat one good application should be OK, it's
  > >pretty thick stuff but don't skimp, however "normal" gelcoat will leave
  > >a sticky tacky surface, so tell your supplier that you need some "wax in
  > >styrene" to add to it (about 1%) the wax will float to the top & seal
  > >the curing gelcoat from air allowing it to cure right through not
  > >leaving a sticky surface.
 >
 > Thanks. I'll ask around about that at the supply places.
 >
  > >If it's a tricky surface (doesn't sound like
  > >it) you can spray some PVA over normal freshly applied gel coat to
  > >achieve the same outcome.
  > >
   > >>
   > >> One of the things I'm still trying to figure out, is how to
   > >> deal with the excess rosin which will want to drip down
   > >> the side of the boat. Can anyone suggest any good way(s)
   > >> of dealing with that issue?
   > >>
  > >
  > > Masking tape & throw away placky drip sheets from a paint shop etc. If
  > >you have a situation which doesn't allow, you can spray PVA over the
  > >lower surfaces (it's cheap mould release agent which sets quickly into a
  > >placky film) then when finished the drips etc will come away easily, the
  > >PVA is water soluble so can just be harmlessly washed off.
  > >
  > >K
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: ??? about fiberglass roofing a houseboat 

<dh_ld.DeleteThis@nomail.com> wrote in message
news:qtbah0pqjavkfa6mmquo2be654grcme5ee@4ax.com...
 > I have a houseboat whose roof has a bunch of thin
 > spider cracks, as well as some a bit bigger.

Is the roof structurally sound?

What you describe seems to be a bit of overkill if the basic roof is sound
and just needs to be made watertight. My houseboat came with a rubber
coating that has been working really well. Check out <a style='text-decoration: underline;' href="http://www.deckrite.com" target="_blank">www.deckrite.com</a>

Rod<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: ??? about fiberglass roofing a houseboat 

On Fri, 13 Aug 2004 17:25:37 -0400, "Doug Dotson" <dougdotson.RemoveThis@NOSPAMcablespeed.NOSPAMcom> wrote:

 >If it just small cracks then laying down more cloth is probably
 >overkill.

I want to add some strength to it. It still feels strong, and
there aren't any spots I feel a danger of falling through, but
it's 30 years old too. I'm thinking if I add another layer of cloth,
or maybe even 2, it should last another 30 years. I'm 45, and
would like it to outlast me.

 >I'm going through the same kind of exersize after
 >removing my teak decks. If the old surface is gelcoat, then
 >laying cloth over it is a bad idea. The gelcoat will have to be
 >removed to get to the existing glass. The secondary bond
 >characterists of resins over gelcoat is not good.

Thanks for that. Other people have said the same thing.
I have two possible approaches in mind in an attempt to
overcome that problem.
1. sand it off, down to the old glass
2. apply a layer of 1/4" plywood

(the following is posted twice in this thread):
I've been told that if I use plywood, unless I use marine grade
it will eventually buckle and swell because only marine grade
is treated in a way which removes all moisture from the wood.
So even if I get a good seal on it, unless I use marine grade
the moister which is contained in the wood will make it swell.
That doesn't really make sense to me since if it's not swolen
when I put it on, I don't see why it would swell later if it doesn't
absorb any more moisture, but two different people have told
me the same thing.

 >The
 >solution that I am using is applying 2 coats of epoxy barrier,
 >then a 2-part polyurethane finish.
 >
 >Doug
 >s/v Callista

Thanks again....I'll look into doing that.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: ??? about fiberglass roofing a houseboat 

On Fri, 13 Aug 2004 18:49:33 GMT, "Calif Bill" <bmckee.nospam.DeleteThis@ix.netcom.com> wrote:

 >You do not need Marine Ply. The difference in Marine ply and normal outdoor
 >ply, is the marine ply will have no interior voids. All the plys are
 >patched before bonding. No voids is good in a transom, with a big motor
 >trying to flex the ply. For normal walking surfaces, a standard ACX with
 >waterproof glue is fine.
 >Bill

(the following is posted twice in this thread):
I've been told that if I use plywood, unless I use marine grade
it will eventually buckle and swell because only marine grade
is treated in a way which removes all moisture from the wood.
So even if I get a good seal on it, unless I use marine grade
the moister which is contained in the wood will make it swell.
That doesn't really make sense to me since if it's not swolen
when I put it on, I don't see why it would swell later if it doesn't
absorb any more moisture, but two different people have told
me the same thing.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: ??? about fiberglass roofing a houseboat 

<dh_ld.TakeThisOut@nomail.com> wrote in message
news:qqo1i0lkg161lvgd10dnmsdbib6d3dch09@4ax.com...
 > On Fri, 13 Aug 2004 17:25:37 -0400, "Doug Dotson"
<dougdotson.TakeThisOut@NOSPAMcablespeed.NOSPAMcom> wrote:
 >
  > >If it just small cracks then laying down more cloth is probably
  > >overkill.
 >
 > I want to add some strength to it. It still feels strong, and
 > there aren't any spots I feel a danger of falling through, but
 > it's 30 years old too. I'm thinking if I add another layer of cloth,
 > or maybe even 2, it should last another 30 years. I'm 45, and
 > would like it to outlast me.
 >
  > >I'm going through the same kind of exersize after
  > >removing my teak decks. If the old surface is gelcoat, then
  > >laying cloth over it is a bad idea. The gelcoat will have to be
  > >removed to get to the existing glass. The secondary bond
  > >characterists of resins over gelcoat is not good.
 >
 > Thanks for that. Other people have said the same thing.
 > I have two possible approaches in mind in an attempt to
 > overcome that problem.
 > 1. sand it off, down to the old glass

The only way to lay down new glass reliably.

 > 2. apply a layer of 1/4" plywood

So how would you bond the plywood to the gelcoat?

 > (the following is posted twice in this thread):
 > I've been told that if I use plywood, unless I use marine grade
 > it will eventually buckle and swell because only marine grade
 > is treated in a way which removes all moisture from the wood.

I doubt it. From what I understand, marine ply just has waterproof glue and
fewer voids.

 > So even if I get a good seal on it, unless I use marine grade
 > the moister which is contained in the wood will make it swell.

I suppose that it depends upon how the ply was stored prior
to you laying it down.

 > That doesn't really make sense to me since if it's not swolen
 > when I put it on, I don't see why it would swell later if it doesn't
 > absorb any more moisture, but two different people have told
 > me the same thing.

Swollen indicates sever moisture content. It can look totally fine
but still have high moisture content. Once you seal it in then the
moisture can cause problems. The best solution of you feel that you
need additional strength is to grind off the gelcoat and lay down
glass.

  > >The
  > >solution that I am using is applying 2 coats of epoxy barrier,
  > >then a 2-part polyurethane finish.
  > >
  > >Doug
  > >s/v Callista
 >
 > Thanks again....I'll look into doing that.

If you don;t need additional structural strength, then this seems to be
sufficient.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: ??? about fiberglass roofing a houseboat 

<dh_ld RemoveThis @nomail.com> wrote in message
news:qqo1i0lkg161lvgd10dnmsdbib6d3dch09@4ax.com...
 > On Fri, 13 Aug 2004 17:25:37 -0400, "Doug Dotson"
<dougdotson RemoveThis @NOSPAMcablespeed.NOSPAMcom> wrote:
 >
  > >If it just small cracks then laying down more cloth is probably
  > >overkill.
 >
 > I want to add some strength to it. It still feels strong, and
 > there aren't any spots I feel a danger of falling through, but
 > it's 30 years old too. I'm thinking if I add another layer of cloth,
 > or maybe even 2, it should last another 30 years. I'm 45, and
 > would like it to outlast me.
 >
  > >I'm going through the same kind of exersize after
  > >removing my teak decks. If the old surface is gelcoat, then
  > >laying cloth over it is a bad idea. The gelcoat will have to be
  > >removed to get to the existing glass. The secondary bond
  > >characterists of resins over gelcoat is not good.
 >
 > Thanks for that. Other people have said the same thing.
 > I have two possible approaches in mind in an attempt to
 > overcome that problem.
 > 1. sand it off, down to the old glass

The only way to lay down new glass reliably.

 > 2. apply a layer of 1/4" plywood

So how would you bond the plywood to the gelcoat?

 > (the following is posted twice in this thread):
 > I've been told that if I use plywood, unless I use marine grade
 > it will eventually buckle and swell because only marine grade
 > is treated in a way which removes all moisture from the wood.

I doubt it. From what I understand, marine ply just has waterproof glue and
fewer voids.

 > So even if I get a good seal on it, unless I use marine grade
 > the moister which is contained in the wood will make it swell.

I suppose that it depends upon how the ply was stored prior
to you laying it down.

 > That doesn't really make sense to me since if it's not swolen
 > when I put it on, I don't see why it would swell later if it doesn't
 > absorb any more moisture, but two different people have told
 > me the same thing.

Swollen indicates sever moisture content. It can look totally fine
but still have high moisture content. Once you seal it in then the
moisture can cause problems. The best solution of you feel that you
need additional strength is to grind off the gelcoat and lay down
glass.

  > >The
  > >solution that I am using is applying 2 coats of epoxy barrier,
  > >then a 2-part polyurethane finish.
  > >
  > >Doug
  > >s/v Callista
 >
 > Thanks again....I'll look into doing that.

If you don;t need additional structural strength, then this seems to be
sufficient.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: ??? about fiberglass roofing a houseboat 

In article <138Tc.20012$9Y6.6338@newsread1.news.pas.earthlink.net>,
"Calif Bill" <bmckee.nospam.RemoveThis@ix.netcom.com> wrote:

 > You do not need Marine Ply. The difference in Marine ply and normal outdoor
 > ply, is the marine ply will have no interior voids. All the plys are
 > patched before bonding. No voids is good in a transom, with a big motor
 > trying to flex the ply. For normal walking surfaces, a standard ACX with
 > waterproof glue is fine.
 > Bill
 >

Actually, there are some other differences, particularly the number of
plys, but in a non-critical and probably dry application (which this
seems to be), ACX will probably do.

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: <a style='text-decoration: underline;' href="http://members.dca.net/jerelull/X-Main.html" target="_blank">http://members.dca.net/jerelull/X-Main.html</a>
Our BVI FAQs (290+ pics) <a style='text-decoration: underline;' href="http://homepage.mac.com/jerelull/BVI/" target="_blank">http://homepage.mac.com/jerelull/BVI/</a><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: ??? about fiberglass roofing a houseboat