Skip to main content

Questions tagged [joists]

Horizontal support structures beneath the floor running between load bearing walls.

Filter by
Sorted by
Tagged with
44 votes
1 answer
206k views

What are the guidelines for holes in joists?

I've been unable to find a good reference for the size/amount/location of holes I can drill through joists. This is mostly in order to pass cabling or pipes through the joist crosswise. Also, what ...
Aaron's user avatar
  • 6,451
7 votes
5 answers
13k views

Repairing a notched floor joist

Situation I was running some new gas pipe and I notched one floor joist and drilled a hole in another. I have now learned that this is not appropriate. This was in the forbidden zone of the middle 1/...
Peter's user avatar
  • 191
44 votes
7 answers
33k views

How to reinforce a joist with plumbing running through it?

After removing the sub floor in my bathroom in order to extend the sewer pipe for the toilet (it's too close to the tank-side wall), I found that the floor joists have extremely large holes cut in ...
Jordan's user avatar
  • 645
6 votes
4 answers
5k views

How should I repair this floor joist that is too short?

My son recently bought a 100 year old house. We have been working on some framing repairs in the basement, and have some questions about the best way to sister some joists. This is a balloon framed ...
SteveSh's user avatar
  • 6,912
12 votes
3 answers
18k views

Is there a limit to the number of holes bored in a joist?

I already know that a hole bored in a sawn lumber joist cannot be within 2" of any edge or any other notch or hole. And that the hole can only be a maximum of 1/3 the depth of the member (...
Tester101's user avatar
  • 132k
3 votes
1 answer
664 views

Running NM and BX Cables – Stackable Staples – Rim Joists - NEC2017/2020

I mocked up some cable runs and was hoping someone could confirm that they don’t break any NEC2017/2020 rules. The wires are run along the rim joists on the upper edge of the wall right under the ...
sil80's user avatar
  • 567
21 votes
3 answers
28k views

Is notching a flange on an I-Joist ever acceptable?

My home builder said that the following notch in a flange on an I-Joist was acceptable, but I've read that you're never supposed to do so. Is that true?
gibbo's user avatar
  • 313
8 votes
2 answers
14k views

Is it OK to drill vertically through a joist?

I just bought a new house and I'm looking to run some cables. One of the areas I would like to run it to would require drilling through a 2x10 sistered joist. Realizing that going through the joist ...
user13655's user avatar
8 votes
4 answers
7k views

Floor joists connection to eaves

Apologies if this is a duplicate. I'm attempting to floor my loft space. It currently has 47mm x 75mm ceiling joists, not enough for a floor. I am going to add something like 47mm x 200mm along ...
Adam Houldsworth's user avatar
7 votes
1 answer
8k views

Do the guidelines for holes in joists apply to band joists?

This question have a great answer with all the guidelines for drilling holes in joists. The question: Are the guidelines the same for band joists? A bit of context: I'd like to add an exterior ...
Danny T.'s user avatar
  • 1,036
6 votes
2 answers
3k views

Can I drill vertically through this from the main floor to the upstairs?

I made a large hole in my wall with hopes of fishing a wires from the main floor to the upstairs. I'm wondering if I can drill vertically through this. I'm asking because it looks integral to the ...
not_entirely_recommended.'s user avatar
4 votes
1 answer
359 views

How Do I Frame an Opening in My Bathroom Floor

I am fixing termite eaten and improperly spaced joists in my home. I need to create space for the bathtub drain fixtures, which are currently riding right up on a joist that runs under the bathtub, ...
Zen00's user avatar
  • 45
4 votes
1 answer
11k views

Where in the span of a floor joist can I drill holes to run wiring?

How far from the end of a 2x12 or 2x10 floor joist can I drill a hole? NEC 502.8 does not give this answer, only that you have to be 2" above or below the edges, not in what part of the span it has ...
kevin's user avatar
  • 41
3 votes
3 answers
10k views

How to hang a chair from the ceiling joists (with attic access)

I'm planning on hanging a chair from the ceiling. From what I can tell the best method is to add a crosspiece above multiple joists, and mount the chair to that using an eye bolt. The problem with ...
Colin's user avatar
  • 133
3 votes
2 answers
33k views

When installing two layers of subfloor, is it okay to secure both layers to joists?

I am in the middle of replacing my subfloor. The old subfloor was two layers, each about 1/2 inch thick, totaling 1 inch. 1-1/8 inch OSB is pretty much out of stock everywhere at the moment so I'm ...
EthanT's user avatar
  • 83
2 votes
1 answer
2k views

How to fix a joist that has been cut out

I’m doing renovations in an old kitchen. I removed the ceiling as it was damaged, old and nasty. I found that when some prior owner renovated the bath above, they cut into the joists to add plumbing. ...
Oldoldhouseguy's user avatar
1 vote
1 answer
420 views

How should I address lengthwise cracks and other issues in old floor joists?

I purchased a house from 1900 about a year ago. One of the biggest problems I have unsurfaced is cut and cracked joists. My questions are as such with pictures below: Can I just jack them up, ...
Eric D's user avatar
  • 11
1 vote
4 answers
3k views

hanging yoga swing from ceiling joists

I want to hang a yoga swing from the ceiling (last floor, ceiling is insulated with some loose substance, if it makes a difference). The yoga swing needs two bolts, one to two meters apart. I'd rather ...
Jeffrey's user avatar
  • 2,065
0 votes
3 answers
884 views

Can a vapor barrier follow the profile of floor joists?

I'm renovating the 4th and top floor of a house built in 1906 in Rotterdam, the Netherlands. The house has masonry load-bearing walls and wooden beams. The current situation is shown in the image ...
Eric's user avatar
  • 185
0 votes
4 answers
14k views

Knee Brace support Hanger for Treehouse

I am going to be building a Treehouse soon, and am researching the best and most cost effective means to do so. I am good on the platform and beams (using Treehouse Attachment Bolts), and am going to ...
mohlsen's user avatar
  • 6,291
31 votes
5 answers
19k views

Is it safe to remove the bottom chords of a series of garage roof trusses?

See attached picture. Looks like an 8x10 cut-out. He wants to lift cars up so he can walk under them. Is this safe? Doesn't removing the joists affect structural integrity?
Lynn Baker's user avatar
16 votes
5 answers
20k views

Contractor cut joist hangers to make them fit

(edited with additional info re. header) We are removing a couple of load bearing walls as part of renos in our home. The engineer specified a W8x21steel beam to replace the load bearing wall. The ...
user105375's user avatar
11 votes
1 answer
3k views

How do I get to the wall cavity above a double floor joist from below?

I am running some new romex for a couple of electrical outlets. One of the outlets is on one side of a wall in one bedroom and the other outlet is on the other side of the wall in another bedroom. ...
Ryan's user avatar
  • 609
7 votes
1 answer
10k views

How should I attach a chin-up bar to floor joists?

I want to mount a chin up bar to engineered I-beam floor joists. Am I safe to mount it directly up into it with lag bolts? If the spacing isn't correct and I span some joists with 2x4s, should I run ...
Mark's user avatar
  • 205
6 votes
3 answers
3k views

Would drilling a small hole through joist / sole plate cause structural problems?

New home owner. I need to wire some ethernet and coax across the basement up into to the first floor wall. The perimeter wall is cinderblock, it is a twin and this is the shared wall. It looks framed. ...
TEEKAY's user avatar
  • 351
6 votes
3 answers
20k views

How do I repair a floor joist which has a hole drilled less than 2 inches from the bottom?

I have three floor joists that have approximately 1/2 inch hole in them less than 2 inches from the bottom. Is there a recommended fix or approved method to correct this to meet code? These joists ...
Terry Rankin's user avatar
6 votes
1 answer
33k views

How can I attach a ledger board to my house?

Spring is here so I finally started to take measurements for materials I will need to build a new deck on my recently constructed home. I just realized that this isn't going to be quite so simple as I ...
maple_shaft's user avatar
  • 3,212
6 votes
1 answer
2k views

How do I fit a joist in this small space?

This is a follow on question from here: Floor joists connection to eaves Since this question, I have been told I need 8" joists for my span and I have exposed my eaves area to see what space I've ...
Adam Houldsworth's user avatar
5 votes
2 answers
2k views

Could I cut out the affected area in a termite damaged joist or would I need to replace the whole joist if it's rotted at the end

So I have a 2x10 floor joist that's only about 5 feet long (short because it only spans a rounded part of my house) which has termite damage at one end for about 1.5 feet. The damage is on the ...
MonkeyBonkey's user avatar
  • 1,209
5 votes
1 answer
4k views

Should I worry about sagging joists?

I have a two story house and some of the joists between the floors are sagging about an inch or two. When I walk around upstairs I can feel the level difference and downstairs you can slightly see the ...
ddonnell's user avatar
4 votes
3 answers
8k views

Is it OK to drill one or two 2 inch holes into a load bearing header in my basement?

tl;dr: Is it OK to drill one or two 2 inch holes into a load bearing header in my basement made of doubled-up 2x10s on top of 2x6s? This area is in the center of my two-story house, and bridges over ...
Kaypro II's user avatar
  • 353
4 votes
4 answers
12k views

What's the best way to insulate an attic with 2x4 joists?

My 1938 home currently has zero insulation (aside from a few fiberglass batts haphazardly tossed about). The ceiling joists are 2x4 (spaced 16 inch OC), rather than the more modern standard of 2x6 or ...
Peter Gambrill's user avatar
4 votes
3 answers
2k views

How to cut hole larger than 1/3 of joist?

I need to run a toilet drain (3”) through three joists (9 1/4”). Code states holes in joists can not exceed 1/3 the size of the joists. Catch is for 3” pipe I need a 3 5/8” hole — which is larger than ...
DA01's user avatar
  • 24.3k
3 votes
2 answers
3k views

Run conduit perpendicular to ceiling joists in garage

I have a sub panel on a finished wall in my garage. I want to add two 20 amp circuits and run them go outlets on two unfinished walls on the sides of the garage. Is it okay to run metal conduit ...
John K's user avatar
  • 143
3 votes
2 answers
5k views

Why are my joists smaller than standard size?

I was preparing to replace a cantilevered rim joist on my house today. I bought a 2x10 treated board to replace it. I cut a piece to use as blocking and found that the board was much wider than the ...
Jon's user avatar
  • 1,687
3 votes
4 answers
48k views

Can I drill 3-1/2" holes through five joists? [closed]

I need to move a toilet to the other side of room approx. 6 ft. I will have to drill a 3.5 in hole for the waste line in five floor joists on the second floor. Can I double them and still drill the 3....
Joe m's user avatar
  • 31
2 votes
1 answer
343 views

Within code, can I notch a joist block?

I'm replaceing a portion of drywall on the ceiling between floors 1 and 2. For the drywall, I plan to add backer boards on edges. The issue is there are joist blocker boards running perpendicular ...
habrockc's user avatar
  • 179
2 votes
2 answers
4k views

Do I need to brace joists after removing basement ceiling?

I'm about to take out the lath & plaster ceiling in the basement of my 1908 house (I'm hiring it out; I know how bad the mess is). Main reasons for doing this are to get access to wiring and allow ...
skaiser's user avatar
  • 160
2 votes
2 answers
17k views

Is deck joist sistering a sloppy repair?

I have a few bad deck joists that I replaced with new PT joists. These repairs are great. Now I have a few more not too bad joists that will be rotted in a few years. I am thinking to add new PT ...
dave's user avatar
  • 209
2 votes
3 answers
962 views

Should I favor a tighter joist interval or more blocking between joists in order to get the most firmness in the deck?

I am planning a deck with dimensions of 14' x 20', where that is 14' out from the house, and 20' along the house wall. This will be an elevated deck with 2' of that outward span cantilevered. The ...
DonBoitnott's user avatar
2 votes
1 answer
2k views

Repair or Replace Cut Floor Joist

After removing an old bathroom floor in a historic structure, in order to sister joists for a level surface to install new subfloor, we found that one of the original floor joists was notched, and ...
mctossy's user avatar
  • 23
1 vote
2 answers
32k views

What is the best way to hang a heavy dynamic weight from a flat ceiling with joists?

I want to hang something like http://www.skychairs.com/ or similar in my living room. If the joists were exposed I would mount a beam between two of them and hang over or through that. However, when ...
Sparr's user avatar
  • 732
1 vote
1 answer
26k views

What is the max span that can be supported by 2x4 floor joists?

We had old 2x4 floor joists sitting in our bathroom that we ripped out as they were rotten and falling apart. 2x4 is ideally our limit of thickness, and I was thinking of having 4 or 5 2x4 joists ...
Suzan Aydın's user avatar
1 vote
2 answers
35k views

Can I use a 2x8 for a ceiling joist and rafters on a 16' span?

I'm planning an addition which will be 16' wide by 27 feet long overall. the roof will span the 16' dimension. my question is, if there is no plan to use the space above the ceiling for storage or ...
DaveF's user avatar
  • 11
1 vote
3 answers
13k views

How can I repair the end of joists sitting in brick pockets?

I have 2x8 joists over an 8 foot span that were eaten by termites on one end. I need to repair all of the joists in a small room. The building is double wythe structural brick that is approximately ...
wolftiger's user avatar
1 vote
2 answers
476 views

How do I attach subfloor around perimeter with vent and exhaust in the way?

I had some water damage. We wanted to remodel anyways, so I ripped everything out, including the subfloor. Now it looks like this: Here's the same angle, color-coded and labelled for reference: ...
Big McLargeHuge's user avatar
0 votes
1 answer
299 views

How do I repair this joist? [duplicate]

Previous homeowner cut a big notch into a joist in the basement to vent a gas water heater. I had the water heater replaced with electric, and now I want to fix the joist. (Photo below, with annotated ...
Andrew's user avatar
  • 126
0 votes
1 answer
2k views

Adding floor joists to an attic

I am trying to add floor joists to an attic and intend for getting decent amount of support for plywood flooring and storage. The existing truss is 13' across and 24'' span between 2x4 ceiling joists....
Anon's user avatar
  • 3
0 votes
1 answer
1k views

How to fix cracked roof joist?

I cut open my ceiling drywall to take a peek in my "attic" (about 20" of vertical space) before I go about having a skylight installed. I have a flat roof and I noticed one of the rafter/joists is ...
dabi's user avatar
  • 973
0 votes
1 answer
3k views

Can I run NM 12 ga circuits on a running board or MultiCable Staples across floor joists use in a basement with an unfinished ceiling?

The original wiring (1994) is along the best route where wires are stapled at the top of the interior wall plate above the finished drywall. I want to run 4 new circuits, but there is no room to ...
Dave Bush's user avatar