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Old 02-02-2009, 02:57 PM   #1
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firring out concrete wall for electric and insulation


What should I use to fir (SP) out cinder block walls that I want to put electrical and insulation behind. There are currently two doors and a window in the garage. I can replace all if needed. My electricion said to use 2x4's so he would have enough room for electrical boxes. If I do this, how do I compensate for the extra space around the doors and window? I will be putting bead board on the strips

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Old 02-02-2009, 04:00 PM   #2
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firring out concrete wall for electric and insulation


To begin with, you can use 3/4" thick pressure treated firring strips. Your electrician may just be trying to get out of some work. You see, he has to knock a hole in the concrete block next to a piece of firring to recess his boxes. Sometimes, that location may not fall at one of the hollow places in the blocks, and he'll have to use a hammer and cold chisel to chunk out enough room out of the solid part of the block for his box to fit. He will have to do that at the door for the switch box too, because the door edges are poured solid.

This hammer work won't kill him, he has to do it everyday in any new construction anyway.

On the wood part... Just border your doors and windows exactly even with the existing block edges with 1 x 4 Pressure Treated lumber. Then you can do the returns (the part that makes a 90 degree turn toward the door or window) with a either a piece of PT, ripped to the width that will fit in there, or you can just use the bead board if there isn't enough room for the thickness of both the PT and your bead board. Just remember to put tar-paper or visqueene behind the bead board to keep it from touching the block wall. It will rot out if you don't.

The best insulation for this purpose is the rigid fiberboard with the shiney backing. It's 3/4" thick, cuts easy with a knife.

Feel free to ask more if this isn't clear.

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Old 02-02-2009, 04:26 PM   #3
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firring out concrete wall for electric and insulation


Is this in the garage?
Have you thought of surface mount?
Or are you finishing the garage as living space & want some insulation?
You will pay more for any "extra" work your electrician has to do
The longer it takes him to do his job, usually the more you pay
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Old 02-02-2009, 04:40 PM   #4
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firring out concrete wall for electric and insulation


Call around. The phone book is full of electricians.
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Old 02-02-2009, 09:53 PM   #5
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If you use pressure treated lumber make sure you use fasteners rated for that use.

Guidelines for Selecting the Proper Connector.
Why was the use of CCA discontinued for residential and general consumer use?
In recent years pressure treated wood received negative publicity mainly focused on the use of arsenic in CCA. The increasing pressure to eliminate the use of CCA resulted in the treated wood products industry voluntarily transitioning from CCA to alternative preservative systems. CCA is no longer being produced for residential or general consumer use.
.
Are these alternative products more corrosive than CCA-C?
Testing has indicated that some of the alternative products are more corrosive to steel and some protective coatings applied over steel than Chromated Copper Arsenate (CCA-C). Contact the treated wood chemical supplier for more information and see the Preservative Treated Wood Technical Bulletin (PDF).
What metals and protective coatings does the Pressure Treated Wood Industry recommend for use with these newer products?
Hot-dip galvanized or stainless steel fasteners, anchors and hardware are recommended by the Pressure Treated Wood Industry for use with treated wood. This has been the position of this industry for years and their position has not changed with the transition to the alternative copper-based products. In the past this industry did not address the required levels of galvanizing, however most of those in the industry now provide information regarding the minimum level of galvanizing that should be used.
The thicker the galvanized coating the longer the expected service life of the fastener, connector, anchor, or other hardware will be.
Electroplated / electro galvanized and mechanically galvanized coatings should not be considered to be hot-dip galvanized. (Class 55, or higher, mechanical galvanizing provides galvanizing equivalent to the hot-dip galvanizing used on connectors and fasteners. Ref. ASTM B695 for additional information.) It is also worth noting that the galvanized coating thickness varies depending on the galvanizing process used. Remember, the thicker the galvanized coating, the longer the expected service life of the steel will be.
Refer to the different chemical manufacturers and/or treaters as well for their recommendations. A list of trade names is included at the bottom of this page.
Are all stainless steels acceptable for use with pressure-treated wood?
All stainless steels may not be acceptable for use with pressure treated wood. Testing has shown that Types 304 and 316 stainless steels perform very well with CCA-C, ACQ-C, ACQ-D Carbonate, CBA-A, and CA-B treated woods. Type 316 stainless steel contains slightly more nickel than other grades, plus 2-4% molybdenum, giving it better corrosion resistance in high chloride environments prone to cause pitting such as environments exposed to sea water.
What is hot-dip galvanizing?
Hot-dip galvanizing is a process of providing a protective coating (zinc) over bare steel. The bare steel is cleaned, pickled, fluxed, then dipped in a molten bath of zinc and allowed to cool prior to inspection and shipping. Additional information is available at www.galvinfo.com. Some anchors and fasteners can be hot-dip galvanized. Steel connectors can be hot-dip galvanized (See below: “What is the difference between Simpson's Hot-Dip Galvanized (HDG) products and products that are hot-dip galvanized after fabrication?” for additional information.) Terms such as G90 & G185 reflect the galvanized coating thickness that meet the ASTM A653 specification for sheet steel.
What is Mechanical Galvanizing?
Mechanical galvanizing is a process of providing a protective coating (zinc) over bare steel. The bare steel is cleaned and loaded into a tumbler containing non-metallic impact beads and zinc powder. As the tumbler is spun, the zinc powder mechanically adheres to the parts. The zinc coating has “good” durability, but has less abrasion resistance than hot-dip galvanized zinc coatings since it does not metalurgically bond with the steel. Some anchors and fasteners can be mechanically galvanized.
What is ZMAX«?
ZMAX« is a thicker coating (galvanized per ASTM A653 with a G185 coating) than the standard hot-dip galvanized coating (galvanized per ASTM A653 with a G90 coating). This thicker coating is available on select Simpson Strong-Tie connectors. Due to this increased galvanized thickness these connectors would be expected to have a longer service life than standard galvanized connectors. See Simpson Coatings Available for additional information.
What is the difference between Simpson's Hot-Dip Galvanized (HDG) products and products that are hot-dip galvanized after fabrication?
There are two processes used to hot-dip galvanize parts: (1) “continuous” hot-dip galvanizing (“Continuous HDG”) and (2) “batch” or “post” hot-dip galvanizing (“Batch/Post HDG”).
Continuous HDG is generally used to galvanize steel coils at various speeds (up to 600 feet per minute) on thinner gauge steels (galvanized per ASTM A653). Simpson uses this type of steel to fabricate most thinner gauge products. Batch/Post HDG is generally used to galvanize heavier individual parts not capable of being fabricated from galvanized steel coils (galvanized per ASTM A123 for connectors and ASTM A153 for fasteners). After being fabricated, the parts are dipped into molten zinc for a longer period of time than Continuous HDG, usually resulting in a thicker coating and more protection against corrosion. Batch/Post HDG can be used on Simpson connectors, such as CC and CB column caps and bases and thicker gauge hangers(14 gauge and thicker).
What products does Simpson have available in stainless steel, ZMAX«, and hot-dip galvanized after fabrication (Batch/Post HDG)?
Simpson has a broad selection of these products. Call factory for availability at 1-800-999-5099, view our updated list of corrosion-resistant products online, or download our flier F-3FINISHES (PDF).
What Simpson products should I use with the new alternative pressure-treated woods?
Stainless Steel is always the most effective solution to corrosion risk. However, it is also more expensive and sometimes more difficult to obtain. To best serve our customers, Simpson is evaluating the options to identify the safest and most cost-effective solutions. Based on our testing and experience there are some specific applications that are appropriate for ZMAX«/HDG or G90 connectors (see Guidelines for Selecting the Proper Connector to select appropriate connector for your situation.) Click here for recommendations for Quik Drive fasteners. See the Preservative Treated Wood Technical Bulletin (PDF).
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Old 02-03-2009, 10:31 AM   #6
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firring out concrete wall for electric and insulation


Willie T - with the 3/4" strips, will that allow for the wiring to be run outside of the block walls? Do I need the tar paper if I'm going to use the rigid board against the cinder block wall? Lastly, can you explain the windows and door any more?
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Old 02-03-2009, 02:56 PM   #7
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firring out concrete wall for electric and insulation


Quote:
Originally Posted by trouble View Post
Willie T - with the 3/4" strips, will that allow for the wiring to be run outside of the block walls? Do I need the tar paper if I'm going to use the rigid board against the cinder block wall? Lastly, can you explain the windows and door any more?
Thanks-Trouble
Yes, the 3/4" will allow both conduit and/or Romex to clear. And Carlton makes a single receptacle and switch 1-1/4" deep with an 8 cubic inch fill rating.

But if you have an electrician who can't or won't work tight (it's a skill), you may just have to bite the bullet and fir out with 1-1/2" stock. But it will be a bit more work for you. And if you use regular 2 x 4's, they will have to be protected from direct contact with the blocks.

You only have to use something like tarpaper where the bead board will otherwise make contact directly with the block wall. This goes for ANY non-pressure treated wood or regular drywall that is going to directly contact a block wall.

This "no contact" stuff is important. You will be creating a mold friendly environment if you ignore it.

As far as the windows and door wrapping goes, I'm attaching a photo that will show you what it would look like done with 3/4". (Try blowing it up with the <PAGE> Zoom feature at the upper right of your toolbar)

This photo was taken looking through a window opening... notice the edge of the PT to the left? This is how you want yours to go. Now, this is NOT the correct way to wrap a window with PT in new construction like this, but it does show how you should do it since your windows are already installed.

TEACHING NOTE: Can you see the way they left some space down at the bottoms (and at some of the tops) of the firring strips? This is so the electricians and telephone and TV people have someplace to easily run their wires without having to cut strips.

Now, what is NOT good are those strips on the back wall that are out of plumb. This will give the drywall people fits. Also (and this is for your wife) the strips above the windows should have been much longer. Let about 18 or 20 inches run past the edge of each window to provide adequate and substantial fastening for curtain rod hangers.

Also, if you anticipate crown molding going in the room, install a 1 x 4 or a 1 x 6 horozontially at the top instead of just 1 x 2.

One more point. Firring strips NEVER go up real close to the corners. Always hold them a couple of inches away from the corners so the drywall guys can hit them with a screw gun. They can't do it if they are tight in the corners... and they will often just leave your corners floating. This is where a lot of those ugly corner cracks come from. (NOTE) It occurs to me that some people reading this later may see this as the way to treat all corners. We're talking firred block walls here... wood corners are best handled a little differently. Not really necessary to go into that here.

Wanna be a building inspector? What in this picture will get your framing red tagged?

Answer: There is a nailing plate missing from the lower chord of one of those trusses in the foreground.
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firring out concrete wall for electric and insulation-furring.jpg  
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Last edited by Willie T; 02-07-2009 at 06:02 PM.
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Old 02-03-2009, 08:33 PM   #8
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firring out concrete wall for electric and insulation


If your wall surface is relatively smooth and you're going to use 2" rigid foam (R-10) adhered to the blocks with 3/4" furring strips on top (fastened through the rigid foam); you'll have 2 3/4" depth. Plenty of room for a shallow box.

If using the above method, seal all your seams and you won't need the pressure treated furring strips.
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Old 02-03-2009, 08:49 PM   #9
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2X2 metal studs

spray foam insulation

green board for the walls

use wood 2X2's around all doors and windows for trim.

keep it simple
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Old 02-04-2009, 12:40 PM   #10
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firring out concrete wall for electric and insulation


Thanks to all, and Willie T, many thanks. I beleive I can handle this and will put it on my long list of honey do's for this weekend. I guess I need to work fast, because as you guessed Willie T, my wife is adding to this "little project" by the hour. It looks like french doors and some cinder block cutting are in my future. Luckily my oldest friend is a general contractor. I can use all his tools, but getting him to tell me a straight story on how to do things is a different story all together. 5 years ago he spent 1 1/2 years with us re-doing the inside of our house. There wasn't enough $ left to do the garage.
If it's okay, I will be asking you questions during this project. Again, thanks for the advise and picture. I'm definitely a picture guy.
Trouble

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