Insulating a roof with no crawl space

Insulating a roof with no crawl space

Just bought a home built in 1950. The roof I suspect has minimal
insulation. To make the ceilings high, the builder has put in no crawl
space and the rafters are visible from inside the house.

The house is only around 1000 sq.ft. It is in San Jose California.

I looked at the archives of this usenet group, and found discussions
on using foam blocks under the composite shingles. This seems fine
but it seems like it is like building a new roof, which could be
expensive.

I am thinking of the following alternatives:

- Add foam from within in between the rafters and blend them with the
architecture.
- Erect an awning (maybe I should call this a tent) that will cover
all of the roof for the hot summer months.
- Put solar panels. They would not only make shade put also generate
electricity for me. However, I hear that solar panels and convertors
etc. can be very expensive.
- Or, put a solar water heating system.


How would one insulate such a roof?


Thanks!

Deguza

Re: Insulating a roof with no crawl space

On May 6, 7:20 pm, Kompu Kid <deg...@hotmail . com > wrote:
> Just bought a home built in 1950. The roof I suspect has minimal
> insulation. To make the ceilings high, the builder has put in no crawl
> space and the rafters are visible from inside the house.
>
> The house is only around 1000 sq.ft. It is in San Jose California.
>
> I looked at the archives of this usenet group, and found discussions
> on  using foam blocks under the composite shingles. This seems fine
> but it seems like it is like building a new roof, which could be
> expensive.
>
> I am thinking of the following alternatives:
>
> - Add foam from within in between the rafters and blend them with the
> architecture.
> - Erect an awning (maybe I should call this a tent)  that will cover
> all of the roof for the hot summer months.
> - Put solar panels. They would not only make shade put also generate
> electricity for me. However, I hear that solar panels and convertors
> etc. can be very expensive.
> - Or, put a solar water heating system.
>
> How would one insulate such a roof?
>
> Thanks!
>
> Deguza

Exposed rafters so you actualy see the roof deck or whatever finish
product is attached? Spray foam would be best, there are R 5 and R 7.2
foams, then finish the ceiling. How thick is the open area in inches
to insulate, you want what is appropriate and maximum in R value for
your area.

Re: Insulating a roof with no crawl space

On Thu, 8 May 2008 05:29:57 -0700 (PDT), ransley
<Mark Ransley@yahoo . com > wrote:

>On May 6, 7:20 pm, Kompu Kid <deg...@hotmail . com > wrote:
>> Just bought a home built in 1950. The roof I suspect has minimal
>> insulation. To make the ceilings high, the builder has put in no crawl
>> space and the rafters are visible from inside the house.
>>
>> The house is only around 1000 sq.ft. It is in San Jose California.
>>
>> I looked at the archives of this usenet group, and found discussions
>> on  using foam blocks under the composite shingles. This seems fine
>> but it seems like it is like building a new roof, which could be
>> expensive.
>>
>> I am thinking of the following alternatives:
>>
>> - Add foam from within in between the rafters and blend them with the
>> architecture.
>> - Erect an awning (maybe I should call this a tent)  that will cover
>> all of the roof for the hot summer months.
>> - Put solar panels. They would not only make shade put also generate
>> electricity for me. However, I hear that solar panels and convertors
>> etc. can be very expensive.
>> - Or, put a solar water heating system.
>>
>> How would one insulate such a roof?
>>
>> Thanks!
>>
>> Deguza
>
>Exposed rafters so you actualy see the roof deck or whatever finish
>product is attached? Spray foam would be best, there are R 5 and R 7.2
>foams, then finish the ceiling. How thick is the open area in inches
>to insulate, you want what is appropriate and maximum in R value for
>your area.

I wonder if these techniques that have been suggested may be hard on
the roofing shingles (if they are heat sensitive, such as your typical
asphalt shingles)? I know here in New England (not a hot spot) that
roofs that have an insulated deck tend to have much lower shingle life
than roofs which have some ventilation built into them.

Re: Insulating a roof with no crawl space

On May 8, 8:03 am, PeterD <pet...@hipson . net > wrote:
> On Thu, 8 May 2008 05:29:57 -0700 (PDT), ransley
>
>
>
>
>
> <Mark Rans...@yahoo . com > wrote:
> >On May 6, 7:20 pm, Kompu Kid <deg...@hotmail . com > wrote:
> >> Just bought a home built in 1950. The roof I suspect has minimal
> >> insulation. To make the ceilings high, the builder has put in no crawl
> >> space and the rafters are visible from inside the house.
>
> >> The house is only around 1000 sq.ft. It is in San Jose California.
>
> >> I looked at the archives of this usenet group, and found discussions
> >> on  using foam blocks under the composite shingles. This seems fine
> >> but it seems like it is like building a new roof, which could be
> >> expensive.
>
> >> I am thinking of the following alternatives:
>
> >> - Add foam from within in between the rafters and blend them with the
> >> architecture.
> >> - Erect an awning (maybe I should call this a tent)  that will cover
> >> all of the roof for the hot summer months.
> >> - Put solar panels. They would not only make shade put also generate
> >> electricity for me. However, I hear that solar panels and convertors
> >> etc. can be very expensive.
> >> - Or, put a solar water heating system.
>
> >> How would one insulate such a roof?
>
> >> Thanks!
>
> >> Deguza
>
> >Exposed rafters so you actualy see the roof deck or whatever finish
> >product is attached? Spray foam would be best, there are R 5 and R 7.2
> >foams, then finish the ceiling. How thick is the open area in inches
> >to insulate, you want what is appropriate and maximum in R value for
> >your area.
>
> I wonder if these techniques that have been suggested may be hard on
> the roofing shingles (if they are heat sensitive, such as your typical
> asphalt shingles)? I know here in New England (not a hot spot) that
> roofs that have an insulated deck tend to have much lower shingle life
> than roofs which have some ventilation built into them.- Hide quoted text =
-
>
> - Show quoted text -

Yes I wasnt thinking, it will have some effect. I dont know what the
procedure is on SIPS construction, if venting is used and how shingles
last. But for metal, slate and tile it would not matter. I dont his
utility costs but they will likely double soon and that may be more
important. Venting could be done by running a spaced sheeting away
from the roof deck, but at what cost, maybe a different type of roof
material would be better.

Re: Insulating a roof with no crawl space

On May 8, 5:29 am, ransley <Mark Rans...@yahoo . com > wrote:
> On May 6, 7:20 pm, Kompu Kid <deg...@hotmail . com > wrote:
>
>
>
>
>
> > Just bought a home built in 1950. The roof I suspect has minimal
> > insulation. To make the ceilings high, the builder has put in no crawl
> > space and the rafters are visible from inside the house.
>
> > The house is only around 1000 sq.ft. It is in San Jose California.
>
> > I looked at the archives of this usenet group, and found discussions
> > on  using foam blocks under the composite shingles. This seems fine
> > but it seems like it is like building a new roof, which could be
> > expensive.
>
> > I am thinking of the following alternatives:
>
> > - Add foam from within in between the rafters and blend them with the
> > architecture.
> > - Erect an awning (maybe I should call this a tent)  that will cover
> > all of the roof for the hot summer months.
> > - Put solar panels. They would not only make shade put also generate
> > electricity for me. However, I hear that solar panels and convertors
> > etc. can be very expensive.
> > - Or, put a solar water heating system.
>
> > How would one insulate such a roof?
>
> > Thanks!
>
> > Deguza
>
> Exposed rafters so you actualy see the roof deck or whatever finish
> product is attached? Spray foam would be best, there are R 5 and R 7.2
> foams, then finish the ceiling. How thick is the open area in inches
> to insulate, you want what is appropriate and maximum in R value for
> your area.- Hide quoted text -
>
> - Show quoted text -

Yes, I believe that is what I am seeing from within inside the house.
The rafters are at least 6" down from the roof.

I can create with 2x2's cells in between the rafters and put foam
blocks then cover the cells with plywood, then stain them to match the
original ceiling color and the exposed rafters.

I wonder if I can use reflective bubblewrap top of insulation instead
of foam. (Here is what I am talking about: * w w w .btubusters . com /attic-c=
eiling-detail.html).
I hear that the R values of these are very good.

Here something similar to my ceiling:

* w w w .loghomebuilders.org/files/images/log-home-master-bedroom-cathedra=
l-ceiling-jj35.preview.jpg

In my case rafters run in the other direction and the distance between
the rafters is far greater. That's why I think I would need to create
cells.

If I were to go with cells filled with foam, is there any ventilation
neede between the foam and the ceiling?

Deguza

Re: Insulating a roof with no crawl space

While searching for insulation on the net I found a real good page:

* w w w .eere.energy.gov/consumer/your home/insulation airsealing/index.cfm/mytopic=11510

Deguza

Re: Insulating a roof with no crawl space

On May 8, 4:03 pm, Kompu Kid <deg...@hotmail . com > wrote:
> While searching for insulation on the net I found a real good page:
>
> * w w w .eere.energy.gov/consumer/your home/insulation airsealing/i...
>
> Deguza

That is a good site, bubble wrap -reflextic? See if there is an
independant lab, a real one, that verified their claims on R value, I
dont believe them. The question is what Zone are you in and what is
the optimal for your zone, I put in R100, it sank to R 70 but it goes
from -20f to 100f where I am. w w w .energystar.gov might give you a
starting point as to what you need. I dont know you weather but I
thought it was a mild area

Re: Insulating a roof with no crawl space

On May 8, 5:29 pm, ransley <Mark Rans...@yahoo . com > wrote:
> On May 8, 4:03 pm, Kompu Kid <deg...@hotmail . com > wrote:
>
> > While searching for insulation on the net I found a real good page:
>
> > * w w w .eere.energy.gov/consumer/your home/insulation airsealing/i...
>
> > Deguza
>
> That is a good site, bubble wrap -reflextic? See if there is an
> independant lab, a real one, that verified their claims on R value, I
> dont believe them. The question is what Zone are you in and what is
> the optimal for your zone, I put in R100, it sank to R 70 but it goes
> from -20f to 100f where I am.w w w .energystar.govmight give you a
> starting point as to what you need. I dont know you weather but I
> thought it was a mild area

Thanks for the link, it has much better information.

Yes, where I am the weather is relatively mild. However, builders
1950's did absolutely nothing to insulate the house.

I am the type of guy who can stand cold (my room temp is around 65 to
68 during the winter), but cannot take any heat --literally, not
figuratively :)

When temperatures rise during the summer, interior in an older
uninsulated house around here goes to 80 to 85. (When I cook or use my
computer, it is more like 85.) This really bothers me. I should add
here that the home does not have an airconditioner.

So my goal is to lower the interior temperature during the summer as
much as possible.

Deguza

Re: Insulating a roof with no crawl space

On May 9, 10:57=A0am, Kompu Kid <deg...@hotmail . com > wrote:
> On May 8, 5:29=A0pm, ransley <Mark_Rans...@yahoo . com > wrote:
>
> > On May 8, 4:03=A0pm, Kompu Kid <deg...@hotmail . com > wrote:
>
> > > While searching for insulation on the net I found a real good page:
>
> > > * w w w .eere.energy.gov/consumer/your_home/insulation_airsealing/i..=
.
>
> > > Deguza
>
> > That is a good site, bubble wrap -reflextic? See if there is an
> > independant lab, a real one, that verified their claims on R value, I
> > dont believe them. The question is what Zone are you in and what is
> > the optimal for your zone, I put in R100, it sank to R 70 but it goes
> > from -20f to 100f where I am.w w w .energystar.govmightgive you a
> > starting point as to what you need. I dont know you weather but I
> > thought it was a mild area
>
> Thanks for the link, it has much better information.
>
> Yes, where I am the weather is relatively mild. However, builders
> 1950's did absolutely nothing to insulate the house.
>
> I am the type of guy who can stand cold (my room temp is around 65 to
> 68 during the winter), but cannot take any heat --literally, not
> figuratively :)
>
> When temperatures rise during the summer, interior in an older
> uninsulated house around here goes to 80 to 85. (When I cook or use my
> computer, it is more like 85.) This really bothers me. I should add
> here that the home does not have an airconditioner.
>
> So my goal is to lower the interior temperature during the summer as
> much as possible.
>
> Deguza

Bubble wrap is not recommended as the R-vale is over stated and needs
an air gap to get the radiant barrier to work. With lower
temperatures the radiant transfer is substantial. The demonstration
they show with the infrared lamps is not realistic. The temperature
of the heat lamp is over 300 deg F (that is as high as the thermometer
I have will go). Since radiation is expediential as the temperature
increases the demonstration is not real.

As for foam, one needs to check with their building code as to what is
allowed per the fire code.

I would do nothing less than 2=94 of foam, would prefer 4=94 or more. As
the years go on the cost of energy is only likely to go up. I am of
the mind set that we should be taking societal benefits into account
and not just the immediate dollar savings. If you find a good source
for societal cost please let me know. Since your goal is comfort I=92d
highly recommend the 4=94 if it can be installed.

Regardless of the foam being on the top or bottom of the roof deck it
will raise the roof temperature (the energy absorbed from the sun has
to go somewhere).

Andy