Re: [time-nuts] Choke Ring Pictures
Joseph M Gwinn wrote:
The tar paper is there primarily to reduce air infiltration when the wind
blows. Now days this purpose is served by the white housewrap, the
original brand being Tyvek.
That doesn't follow. Most houses in the US have attics below the shingles
that are open to free air by way of soffit vents.
Even in the case of cathedral ceilings, the space below the roof sheathing
is open to the outside air... to not do so will seriously compromise the
shingle life due to excess heating.
Tyvek is never used on roofs. It is always too slippery for walking on.
Water that blows past the shingles is stopped by the tarpaper or
housewrap, keeping the sheathing and insulation dry.
Nope.
There are two layers of shingles over any given part of the roof. Modern
asphalt shingles have an asphalt glue down strip that ties the shingle
tabs to the course below. There isn't going to be any air infiltration
of significance.
Builders and roofers are of a mixed mind over tarpaper. Many leave it
off because it is a hazard to the roofers. The stuff is very slippery
if it gets even the slightest bit wet.
The roof stays dry either way.
-Chuck Harris
I think tar paper basically has two functions these days- it's a cheap backup in case the roofers don't install correctly, and the lines on the paper are used as a guide to install the shingles.
Dave
----- Original Message -----
From: "Chuck Harris" cfharris@erols.com
To: "Discussion of precise time and frequency measurement" time-nuts@febo.com
Sent: Tuesday, March 16, 2010 11:44:49 AM GMT -08:00 US/Canada Pacific
Subject: Re: [time-nuts] frying pan antenna
Joseph M Gwinn wrote:
The tar paper is there primarily to reduce air infiltration when the wind
blows. Now days this purpose is served by the white housewrap, the
original brand being Tyvek.
That doesn't follow. Most houses in the US have attics below the shingles
that are open to free air by way of soffit vents.
Even in the case of cathedral ceilings, the space below the roof sheathing
is open to the outside air... to not do so will seriously compromise the
shingle life due to excess heating.
Tyvek is never used on roofs. It is always too slippery for walking on.
Water that blows past the shingles is stopped by the tarpaper or
housewrap, keeping the sheathing and insulation dry.
Nope.
There are two layers of shingles over any given part of the roof. Modern
asphalt shingles have an asphalt glue down strip that ties the shingle
tabs to the course below. There isn't going to be any air infiltration
of significance.
Builders and roofers are of a mixed mind over tarpaper. Many leave it
off because it is a hazard to the roofers. The stuff is very slippery
if it gets even the slightest bit wet.
The roof stays dry either way.
-Chuck Harris
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
Putting the paper down doesn't hurt, so I always do it, but you would
have to do a really lousy job for it to help. The only time I can see
it really helping, after the shingles are on, is if you have a massive
tear off due to a storm.
I frequently leave a new roof in tar paper for several weeks before I
can schedule time to put the shingles on. That is the real use for
tar paper in roofing.
I never use the lines on the paper. I layout the roof myself,
using a chalk line to mark out the courses.
-Chuck Harris
d.seiter@comcast.net wrote:
I think tar paper basically has two functions these days- it's a cheap backup in case the roofers don't install
correctly, and the lines on the paper are used as a guide to install the shingles.
Hi
So has anybody tossed a bunch of shingles and tar paper in the microwave to
see what happens yet?
Bob
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Chuck Harris
Sent: Tuesday, March 16, 2010 4:33 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] frying pan antenna
Putting the paper down doesn't hurt, so I always do it, but you would
have to do a really lousy job for it to help. The only time I can see
it really helping, after the shingles are on, is if you have a massive
tear off due to a storm.
I frequently leave a new roof in tar paper for several weeks before I
can schedule time to put the shingles on. That is the real use for
tar paper in roofing.
I never use the lines on the paper. I layout the roof myself,
using a chalk line to mark out the courses.
-Chuck Harris
d.seiter@comcast.net wrote:
I think tar paper basically has two functions these days- it's a cheap
backup in case the roofers don't install
correctly, and the lines on the paper are used as a guide to install the
shingles.
time-nuts mailing list -- time-nuts@febo.com
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https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
mike cook wrote:
Yes Bruce, I also think that azimuth dependent masking would be useful.
I have been suffering from strong reflections from facing buildings at
50m to 100m, which cause sharp departures from the average PPS TI
While telling the nav algorithms inside the box would be the most clever
way, you could also put up a fence of RF absorber (or perhaps even
conductive sheet) at some distance from the antenna. The wavelength is
on the order of 25-30 cm, so a fence a couple meters away is in the "far
field"
No, my wife likes our microwave to remain tar free.
-Chuck Harris
Bob Camp wrote:
Hi
So has anybody tossed a bunch of shingles and tar paper in the microwave to
see what happens yet?
Bob
Hi
It's all in the name of science !!!!
Bob
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Chuck Harris
Sent: Tuesday, March 16, 2010 5:23 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] frying pan antenna
No, my wife likes our microwave to remain tar free.
-Chuck Harris
Bob Camp wrote:
Hi
So has anybody tossed a bunch of shingles and tar paper in the microwave
to
see what happens yet?
Bob
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time-nuts-bounces@febo.com wrote on 03/16/2010 02:44:49 PM:
Date:
03/16/2010 03:17 PM
Subject:
Re: [time-nuts] frying pan antenna
Sent by:
Joseph M Gwinn wrote:
The tar paper is there primarily to reduce air infiltration when the
wind
blows. Now days this purpose is served by the white housewrap, the
original brand being Tyvek.
That doesn't follow. Most houses in the US have attics below
the shingles that are open to free air by way of soffit vents.
Ahh. I was talking about the side walls, not the roof. We do lots of
wood shingles and clapboard on walls here in New England, but the roofs
are usually asphalt shingles.
Even in the case of cathedral ceilings, the space below the
roof sheathing is open to the outside air... to not do so will seriously
compromise the shingle life due to excess heating.
In the summer, and cause ice dams in the winter.
I gather from your email provider that you are in the Washington, DC area,
where summers are far more brutal than up here in the frozen north. (I
used to live in Washington and Baltimore.)
Tyvek is never used on roofs. It is always too slippery for walking on.
True.
Water that blows past the shingles is stopped by the tarpaper or
housewrap, keeping the sheathing and insulation dry.
Nope.
Side wall versus roof.
There are two layers of shingles over any given part of the roof. Modern
asphalt shingles have an asphalt glue down strip that ties the shingle
tabs to the course below. There isn't going to be any air infiltration
of significance.
I don't know how true that will be after a few years, but the overlap
keeps the water out, unless there is an ice dam.
Builders and roofers are of a mixed mind over tarpaper. Many leave it
off because it is a hazard to the roofers. The stuff is very slippery
if it gets even the slightest bit wet.
The roof stays dry either way.
Here in New England, ice dams are the big issue, and lots of people have
an EPDM rubber sheet put down between sheathing and roof shingles for this
reason. Heavy tarpaper or tarred felt was supposed to perform this
function as well, but as you say its effectiveness was always debated,
especially after it had dried out and cracked. The rubber is supposed to
last 50 years, though.
Joe Gwinn
-Chuck Harris
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