# Extending 2x4 to 2x6



## ddawg16 (Aug 15, 2011)

News alert....

A 2x4 is actually 1.5 x 3.5....been that way for a long time....2x6 is 1.5 x 5.5....

Maybe a bit more information...like where you live....what the existing wall is like....we are assuming that you have already pulled all of the drywall off...

Lacking any more info....if it was me....I would rip some 2x6's down the middle...or just sister 2x4's to the existing studs so that they stick out the depth you want.


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## Gary in WA (Mar 11, 2009)

Compressing it 1/2" will reduce the total R-value by around R-2, similar to R-15 (high density) fiberglass in 3-1/2 to 2-1/2" wall; http://www.greenbuildingadvisor.com/sites/default/files/Compressing%20fiberglass.JPG

Gary
PS. you will gain in density though; http://books.google.com/books?id=e5...berglass increases density per inches&f=false


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## 123pugsy (Oct 6, 2012)

Rip some strips of 1/2'' plywood to put behind the 2x2's.


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## Fix'n it (Mar 12, 2012)

ddawg16 said:


> or just sister 2x4's to the existing studs so that they stick out the depth you want.


i did that to square up a wall, and fur it out 1". it was a PITA to get the roxul to fit properly = every piece of roxul had to be custom trimmed/fitted = no fun at all. 

biddle
decide what you want in the wall. find the thickness of it all. rip strips to the right size. caulk and nail them to the 2x4's.

been there, done both.


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## jazzop89 (Apr 28, 2017)

The term for your (nominal) 2x2 extenders is "furring strips". You can do this, with some limitations depending on the applicable codes. I have investigated this myself, as my house is also 2x4 construction (although real heartwood pine 2.0"x4.0" from the good ol' days). The main limitations I have found are related to the following areas, which may or may not be relevant in your case:

Below-grade walls
Fire-rated walls (generally commercial code only)
Exterior-facing walls
Type of wall covering being attached
Stud spacing (I believe you can't fur out studs spaced >24" o.c.)
Thickness of wall covering (very thin panels can't be furred out)
Furring has some potential impact on the routing of wiring in the wall
Furring is definitely a better option than compressing insulation, which in most cases undermines the entire design and function of the insulation product.

I may run into a problem with not being able to fur out far enough, as I am trying to achieve an extreme level of efficiency for LEED/PassivHaus. Since the answers are relevant to the OP's project, I don't think it would be hijacking the thread to ask:

1. Could I sister up 2x8s in order to get even more depth? 
2. Does anyone know what sort of search terms I should use in the IRC/IBC to find info on "furring by sistering"?
3. Can I sister them with a slight offset so that the total depth is >8"?


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## Clutchcargo (Mar 31, 2007)

OP, 
Is ripping 2x4s out of the question? you would loose a little depth from 5.5" but only about 1/4" or R1.
I call them sleepers.


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## ddawg16 (Aug 15, 2011)

4 year old thread....


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## BIG Johnson (Apr 9, 2017)

ddawg16 said:


> 4 year old thread....


His issue was pretty complicated so he might still be looking for a solution.


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## NotyeruncleBob (Mar 9, 2017)

jazzop89 said:


> I may run into a problem with not being able to fur out far enough, as I am trying to achieve an extreme level of efficiency for LEED/PassivHaus. Since the answers are relevant to the OP's project, I don't think it would be hijacking the thread to ask:
> 
> 1. Could I sister up 2x8s in order to get even more depth?
> 2. Does anyone know what sort of search terms I should use in the IRC/IBC to find info on "furring by sistering"?
> 3. Can I sister them with a slight offset so that the total depth is >8"?


If you're thinking of going that deep with the wall, why not just go double stud wall? (basically two parallel walls with lots of insulation in between)


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## 123pugsy (Oct 6, 2012)

jazzop89 said:


> ........................................
> 2. Does anyone know what sort of search terms I should use in the IRC/IBC to find info on "furring by sistering"?
> ...........................................................


There's not much about it in our code. Probably similar all around.
The furring is only holding drywall. If it's screwed at the same intervals as drywall requirements, the inspector should have no complaints.
The table below could not cope and paste properly but you can search using some of the terms.


From the OBC:

9.23.10.5. Support for Cladding Materials
(1) Corners and intersections shall be designed to
provide adequate support for the vertical edges of interior
finishes, sheathing and cladding materials, and in no
instance shall exterior corners be framed with less than the
equivalent of two studs.
(2) Where the vertical edges of interior finishes at wall
intersections are supported at vertical intervals by blocking
or furring, the vertical distance between such supports
shall not exceed the maximum distance between supports
specified in Section 9.29.

Table 9.29.3.1.

Size and Spacing of Furring

Forming Part of Sentence 9.29.3.1.(1)
Item Column 1 Column 2 Column 3 Column 4
Maximum
Spacing
of Furring,
mm
Minimum Size of Furring, mm
Maximum Spacing of
Furring Supports
Continuous
Supports
406 mm
(o.c.)
610 mm
(o.c.)
1. 305 19 × 38 19 × 38 19 × 64
2. 406 19 × 38 19 × 38 19 × 64
3. 610 19 × 38 19 × 64 19 × 89

9.29.3.2. Fastening

(1) Furring shall be fastened to the framing or to wood
blocks with not less than 51 mm nails.


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## jazzop89 (Apr 28, 2017)

ddawg16 said:


> 4 year old thread....


So? I care about the issue and have subscribed to the thread. I never understood why there is a subset of people on various forums who have an aversion to threads older than yesterday. I'd rather follow a single old, informative thread that has a greater likelihood of keywords and synonyms being spelled correctly than have to filter through dozens of short threads or, even worse, not even know a thread exists because the title and/or posts are misspelled or use non-standard terminology.


NotyeruncleBob said:


> If you're thinking of going that deep with the wall, why not just go double stud wall? (basically two parallel walls with lots of insulation in between)


Because I'm not familiar with this technique. Care to elaborate or provide links to examples/tutorials?


123pugsy said:


> There's not much about it in our code. Probably similar all around.
> The furring is only holding drywall. If it's screwed at the same intervals as drywall requirements, the inspector should have no complaints.
> The table below could not cope and paste properly but you can search using some of the terms.
> 
> ...


What is "OBC"?
I hope to find a suitable wall covering other than gyp board, such as hardwood direct to studs/bracket system or a synthetic with its own added R-value. So I'll have to be extra thorough with the vagarities of the codes because they are so biased toward gypsum/plaster.


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## 123pugsy (Oct 6, 2012)

jazzop89 said:


> So? I care about the issue and have subscribed to the thread. I never understood why there is a subset of people on various forums who have an aversion to threads older than yesterday. I'd rather follow a single old, informative thread that has a greater likelihood of keywords and synonyms being spelled correctly than have to filter through dozens of short threads or, even worse, not even know a thread exists because the title and/or posts are misspelled or use non-standard terminology.
> 
> Because I'm not familiar with this technique. Care to elaborate or provide links to examples/tutorials?
> 
> ...



Ontario Building Code.
Most are similar.


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