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Volume 3 Issue 7“Building Confidence”July 2005



Summer is winding down for another year, time to get ready for Fall. (For tips on preparing your house for Fall see my article Seasonal 1: Fall at

Welcome to our new readers and those who have been with us for a while.

What's New

Not too much has changed on our website since our last newsletter, since we have both been on vacation. Dan managed to upgrade the Stair Calculator at by adding the choice of headroom required.

Ask Away!

The following questions and answers are typical of what I do during the month:

I would like to replace the original wood frame, single pane windows in my
brick faced garage with vinyl double glazed windows.  Is replacing them with
original construction windows out of the question and would it be better to
leave the frame intact and install replacement windows?

Your feedback is appreciated.


Hi Dan,

You should be able to pull out the old wood jamb and replace it with a new vinyl window. Make sure to tell your salesman what you are doing and he will make up a renovator window for you, custom size without a flange. This is not that much more than the stock windows.


How do I figure out the height to place my handrail on a post to post
situation go up the steps and at the landing?


Hi Mark,

The handrail going up the stairs should be 34" to 38" vertically measured from the nosing to top of handrail. For a landing, top of handrail is 36", over 6' high it should be 42" above the finished floor.

Codes vary in different parts of the country.


hi I'm replacing shower line (no tub) in a condo; and they will not allow the use of plastic pipe. So does one use galvanized ? or copper? is copper better ? if galvanized does one get pipe cut at hdw. store or home center ? and if threaded does one use teflon tape? any other suggestions? thanks Charlie

Hi Charlie,

Yes, use copper pipe. Galvanized is not used too much these days. Use Teflon for all threaded connections.

Soldering copper pipe is not that hard. Use a piece of old metal flashing behind the pipe to prevent catching the wall on fire. Have a pail of water handy, before turning the water off. Remember the toilet tank has water, in an emergency.

Clean the inside of the fitting and outside of the pipe until it is shiny clean. Use flux on all joints. Heat the fitting, not the pipe. Solder will go in the direction of the heat. Make sure the pipe and fitting are soldered all around. Once the water is turned back on, and there is a leak, it is a problem to reheat the joint to pull it apart and start over. Be very fussy the first time!! There can be no water in the pipe when soldering!!


How much space for a toilet, is normal (the smallest) to have between a vanity and a bath tub? Thanks. Randy

Hi Randy,

Our code requires at least 30", usual is 36".


Hi this is Clifford... again, you have helped me with a bunch of stuff and so has your brother, and it always works out just great, OK here is a new one, boy i must be getting old or something as i did this in my bedroom and be darned if i can remember how i did it, OK 1 light in the middle of the room, now to switches, one at each end of the room, ether one can turn the light on or off. how do i wire this??? any chance you could send me like a drawing showing the wires and which goes where. LOL I know i know this but i am a blank. Thanks and talk to ya later. Have a great one. Oh in case you are wondering who i am i am the person with the 100 year old house that had the real steep stairs with only a 7" 6" ceiling and no room to run the stairs out farther. Cliff

Hi Cliff,

Good to hear from you!!

I can send you a sketch of the 3 way switch. I need to know which box the power is coming into, at the light or at the switch box??

Remember the switches are both 3-way switches they will have 3 terminals on them, not just two.



hey Dave, cool yes i remembered the 3 way switches, its the wires
i am a blank on, OK this one already has power at the light it
self not the switch, But if you could also send me the other layout
to with the power at the switch, I will put both in my Dave Osborne
file, as i will need it down the road. The file is getting a bit fat
and very handy, LOL i think one day it will be as big as a book.
But don't worry i will not print it, it will be something i pass to
my son when the time comes that he is married and has a home of
his own, Thanks. This is all i have left to wire in the kitchen
so am just waiting on your help. then time for new top 3/4 in flooring,
then sheetrock, texture, paint. then tile linoleum. almost there. LOL.
Have a great one.


Okay got them:

Drawings showing how to wire a three way switch with the electric power going to either the light switch or the light fixture.

I think they are pretty self explanatory. Choose the drawing to match your power feed position.


Dave, If I use staples for a luan underlayment(for Linoleum in a bathroom), what size is best? Also, I thought the underlayment should end up half way through the doorway, but someone just told me only 3/4 inch and the carpet will be laid in the hallway and go through the doorway 4 inches. Mike ( from Kankakee,Il. )

Hi Mike,

If the underlay is 1/4" or 3/8" the staples are 1 1/8" long and should extend at least 85% into the sub-floor, but not into the joists. These are chisel point narrow crown staples used with an 18 gauge air nailer. Otherwise use 1 1/4" ring nails. Keep the staples parallel to the grain so they won't splinter and will set themselves below the surface. I always check the floor after stapling with a 12" drywall knife and sliding it along the floor to see if it catches any staple heads that didn't go below the surface. A hammer blow will smarten it up.

The joint of different flooring is made under the door, in the center, so that from either side, when the door is closed, you only see the flooring in that room.


Hello Dave, Hugh here, the lapeyre stair guy. (nope haven't built them yet but I will someday) I'm in the process of building the angled stairway that you also helped me with. I'm having some trouble with the tread dimensions and the run dimension on the inside of the 36" corner but I'm mocking things up with cardboard and level and I'll figure it out before I start cutting the inside stringer. On to my new question. While working on the stairs my lovely bride Myra asked me if we could add a spare bedroom and bathroom over an existing ground floor bedroom and bathroom. I said sure we could. :-) The existing ceiling joists of the downstairs bedroom are 2x6 on 24" centers. There are two exterior walls in the existing bedroom (EB) that are 2x6 on 16" centers. The two other walls are interior walls that are 2x4 on 16" centers. The EB is not all right angles corners. The narrow end of the room is 10'6" wide and the wide end is 13' 2" wide. To span those widths the online calculator I use says that #2 douglas fir-larch, using a Deflection Limit rating of L/360, floor joists will span 14'2" when on 12" centers and 12'9" when on 16" centers. So I demo the existing roof, ceiling and ceiling joists. I reframe using 2x8 floor joists spaced 16" on center until I need to space them at 12" on center. Then I sheath the floor and then build the walls and roof just like it was on the ground floor, right? I can send you a rough drawing or a photo or two if it'll help clarify anything. Take care. Hugh Onion Creek, WA

Hi Hugh,

My tables say 2x8 at 12" centers will span 13.75' and at 16" centers, 12.80'. A 2x10 will span 14.79' at 16" centers. Both spans are if the joists are strapped and with bridging. By using 5/8" tongue and groove plywood glued and nailed or screwed will also increase the span and make the floor stiffer.

You don't necessarily have to remove the 2x6 ceiling joists and ceiling. You could sister the or 2x8s to the existing 2x6 joists. This helps the 2x8s to be stiffer and also not disturb the existing ceiling unless you want to. Just nail the 2x8s along the 2x6s with an air nailer to keep from disturbing the ceiling finish on the 2x6s. You could also screw the 2x8s to the 2x6s with 3" screws using a power drill as a screwdriver, rather than hammering the nails in to loosen the drywall on the 2x6s.


Hello Dave.

Thanks for the information.

What grade and type of lumber is your table using to give you those

I'd rather not tear out the existing ceiling so sistering in 2x8s
sounds like a good way to go.  What is the nailing(screwing) schedule
for sistering joists?

My wife is getting excited about this addition idea but now she thinks
it would be better to make the upstairs addition a rec room for when
our daughter's friends come over.  So I was thinking I would leave the
existing ceiling and joists alone and use a 2x6 block btw the existing
joists above the top plates and fasten the new 2x8 floor joists to them.
That way the new floor joists are an inch and a half above the existing
ceiling surface and not touching the existing ceiling joists.
That should help to reduce noise from upstairs being transmitted
downstairs.  Do you think that is a reasonable option to consider?
I would have to figure out a way to place blocking without it touching
the existing joists...


Hi Hugh,

We have Span Tables on our website at

Our tables are based on the two lumber stamps readily available for framing in the local lumber yards. Hem/Fir includes Western Hemlock and Amabilis Fir and SPF includes Spruce, Pine, Fir which includes all species of Spruce except Coast Sitka Spruce, that is Jack Pine, Lodgepole Pine, Balsam Fir and Alpine Fir.

Douglas Fir and Western Larch is in a separate category, not included in our tables.

The web page explains our code from which the tables are based. I only included those spans using Construction and Standard grades or #1 and #2, referred to as #2 and better. It's pretty tough to get all #1 lumber these days.

Nailing for sistering joists is 2 nails, one on top, one on the bottom every 16" using 3" nail.

A better way for sound proofing that we use for joists is a Z-strip or acoustic strip. One flange is screwed to the joist the other flange is screwed to the drywall. Works good for uneven ceiling joists, too. I did this when I built a rental suite in a basement for a client, who was very particular about noise from his tenants. I used the existing ceiling/floor joists, insulated with fiberglass batts between the joists fastened on the Z-strips and attached two layers of 1/2" drywall. You couldn't hear much music or sounds from the upstairs. Fiberglass insulation absorbs the ambient sounds from the air and the drywall helps stop the radiating sounds of feet on the floor, etc.

What you describe with the ceiling joist being offset with the floor joists is good. I built a duplex near where I live and the party wall had the walls separated from each other by a 1" airspace. The building inspector required a strip of sheet metal over the gap between the two at floor levels for a fire stop. I only nailed up the one side on top of the wall plates and left the other side floating. It worked well with 5/8" drywall on each side, as well as insulation between the studs.


Hello Dave, Can you tell me what amount of vents should be in the skirting of a mobile home? Thank You

Yes, the area under a mobile home is considered as a crawlspace under a house, if it is not heated. That is a vent area of 1 square foot for every 538 square feet of floor area. Vents should be uniformly distributed on opposite sides of the mobile, and designed to prevent the entry of snow, rain and insects. You can purchase these crawlspace vents made out of colored plastic which will slide and close during the cold months.


Building a second floor. Existing ceiling beams are 2x6. I am trying to provide room for duct work. Can I use 2x6s every 48" across the existing beams and then add 2x? over existing beams.. and tie the grid together. My greatest distance is from bearing walls is 22'. Thank you


I need more info for this type of question.

Are the 2x6s beams or single joists and at what centers? What is the span of the ceiling joists and what is the width and height required for the ducts?


Hi Dave,
I've attached a layout of the existing structure... with proposed
extensions for new addition/second floor. The existing 2x6s are
ceiling joists, 16" on center. Their longest span as you can see
from the layout is 18"... however I am extending a section by 3-4"
therefore the second floor will have a span of 21-22".
As far as duct sizing... that of course would depend on available
width/height. An existing main return is 16 x 20". I've been told
that I have to rip out everything and use engineered 14" I- Joists.
I would like to keep the existing 6" ceiling joists and lay additional
2x6's across them, perhaps every 4' (keeping existing electric,
cable etc.) Then place a third joist parallel to the originals and
strap/tie the three together.  It seems to me that  with the proper
top I-Joist this should provide more than adequate strength with
little or no deflection. But, does it meet the code? Please let me
know your thoughts.

Hi Frank,

When non-conventional framing is done, we have to be very careful the framing is sufficient to support the load.

In my opinion, You should go with the advice of an engineer who designs I-floor joists. These things are light and extremely strong. They, however, have to be designed and approved by an engineer. They also will help give ideas on the ducting issue. Something like re-designing the height and width of the duct so that it will fit into the space of the I-joist and allow lateral structural pieces, like 2x4s between the I-joists above and below the duct work. This would allow the fastening of the subfloor and ceiling continuous across the joists.

What you are describing may work if you truss the top joist with the bottom joist with the proper size top joist and proper web layouts. This is not according to the code. The code can be overwritten by the pen of an engineer who designs such a system and approves it for your particular house. I would listen to his advice on this one.

With your span of 21 or 22', this is right off my span tables for conventional dimension lumber floor joists.

Good luck,


Dave, what should I use to attach the galvanized window wells to my concrete foundation? I thought maybe tapcons, but I think the heads of those are too small. I see some other options, but I'm not sure which is best.


I've never had much luck with the tapcon. You need to use the special size drill bit that comes with it. I prefer a wedge type of anchor for concrete that leaves a bolt exposed for a nut and washer. You should be using a 1/4" anchor, at least.


Dave, What do you recommend to attach window wells to the foundation?
Also, can I use my cordless nailer with the 8D ring shank nails to
put down 1/2 inch plywood underlayment? Or should I stay with nails
specifically labeled for underlayment?


Hi Mike,

Sorry for the delay in getting back with you, I've been on vacation.

I answered your first question in an earlier email.

Yes, for 1/2" plywood, 8D nails are good, even 7D are good. Your underlay is a bit thick, usually it is 1/4" or 3/8" and staples are used. If this is for lino maybe check with the lino installer. They are pretty fussy when it comes to their warranty. I don't see any problem as long as the heads are slightly below the surface and the nails used are ring shank and spaced according to the specs of the lino professional.


Dave, The reason your site is so good is because we get answers from the source. I hope you had a very enjoyable vacation and Dan will have one as well. I hope to be up in Bellingham, Washington in the next few weeks to visit an old army buddy. I must say your area is beautiful. My wife and I love it. Thanks again for your site and your info at a very reasonable price.

Thank you very much for your email. It really perked me up.

My vacation was great. I've never been away from the computer for so long, but this time I wasn't visiting anyone's home.

Dan will be back on Aug 8th, from a tour of Europe. His wife is from England and has relatives spread out over Europe. This gives them a great opportunity to visit them and see the countries at the same time. Say hi to Bellingham for me. I spent the odd hour at the Shakey's Pizza Parlor down there as a teen when I lived in Vancouver, BC. Good memories!!


That's it for another issue. Dan and I hope you enjoy reading this newsletter and encourage you to forward it on to those who may benefit from it.


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