[Build]

We need to run 3 6" inch ducts to the other side of our center support beam in our basement. Is it safe and code-approved to cut a hole in the 2" x 10" where the red circle is located? There is actually two 2" x 10" back to back where the red circle is.

Below are two pictures. One shows the desired hole (red circle) to be cut and the other shows the center support beam and floor joists.

 

[Aggie67]

I haven't figured out what you've got there. I see a Weyerhauser microlam, and then your red dot. Not sure what the stuff between those two are. It actually looks a gap. What's up with the microlam, is it supporting those joists?

 

[Build]

I wish I had a better picture showing the entire basement. The first picture shows the floor joist running to the center of the house where the main support beam is. This support beam is about 16' long and 20" tall. The second picture shows the support beam. There is a gap between the support beam and the 2" x 6" (or something like that) that is horizontal with the floor directly above the support beam. Then the floor joist sit on top of the 2" x 6" above the support beam. The 2" x 10" we would like to cut a hole in is at the end of the floor joists (the board with the red circle in the first picture).

The house was a modular house which came in 3 pieces. Two of the pieces come together right there in the middle. The beam was used in the part of the basement so we could have a 16' long opening with out a support post.

Does that make sense?

 

[jogr]

I'm trying to figure out why you've got what looks like a double rimboard in the middle of your house sitting on a flat 2x10 that is supported by flat 2x6 shims spaced at 4 ft oc over the central beam. Is this one of those manufactured houses that comes in two halves that are joined together on-site?

 

[Build]

I'm trying to figure out why you've got what looks like a double rimboard in the middle of your house sitting on a flat 2x10 that is supported by flat 2x6 shims spaced at 4 ft oc over the central beam. Is this one of those manufactured houses that comes in two halves that are joined together on-site?

Yes it was a manufactured house. Here are some additional pictures. The first picture shows the support beam before the house was set. That is the support beam in the first pictures. To the back of the house there are support posts every 8'. The beam was used so in the front of the house we would not need a support post.

 

[Aggie67]

Important question: is the joint between the two sides sitting directly over that microlam? In other words, are the shims supporting both rim joists?

Also, I would have a real problem with this, if this was my house. Somebody didn't do a good job. No reason for a 3-1/2" gap between the top of the microlam and the bottom of the prefab structure. Somebody screwed up. Did it pass inspection?

 

[Build]

Important question: is the joint between the two sides sitting directly over that microlam? In other words, are the shims supporting both rim joists?

Also, I would have a real problem with this, if this was my house. Somebody didn't do a good job. No reason for a 3-1/2" gap between the top of the microlam and the bottom of the prefab structure. Somebody screwed up. Did it pass inspection?

Sorry to sound ignorant but what is a "rim joist"? So you are saying that the bottom of the prefab should have been sat right on the microlam (center beam)?

There has not been an inspection. Should we just get an inspection and ask them if cutting the desired hole is ok?

 

[Aggie67]

I'm referring to the marriage line running along that microlam, where the two sections of the house came together.

My advice is to consult with the builder and the company that made the modular home. Bring up all of the issues: the gap, location of the marriage line relative to the microlam, and where you want to make a penetration. They're taking liability for the design and construction. They should be the ones that are consulted.

 

[Build]

Yes the marriage line is in the middle of the microlam. There is actually 3 microlam beams side by side which make up the center beam. Then there are 2 or 3 pieces of 2" x 8" (you can see two in the pictures) which sit on top of the microlam beam. Then the sill plate of the prefab house sits on top of the pieces of 2" x 8".

We talked to the company and they said we should talk to a home inspector about the hole.

Are there any guide lines to go by when picking an inspector? Any certain certfication is look for - ASHI, NACHI, ICC, etc...?

Thanks for all the help!!

 

[Gary in WA]

Build, the inspection is not for the hole, it is because that is a lame way to connect the floor system together over a bearing beam. The Inspector would be from the Building Department to OK the building for final occupancy. The mess you have would not pass inspection. To back fill an 8' basement without bracing inside as they did is not to the minimum safety code. Without braces, the fresh concrete walls could easily crack from all the dirt (clay) compacted from the bobcat).

Page 3- 1st para.- General: Do not install back fill 4ft. and over until walls anchored to floor [404.1.7] IRC (1838.1) UBC
http://www.codecheck.com/cc/images/CC5thEdSample.pdf

The beam appears to be about a foot in the wrong location. It looks like it's only holding up this side (picture side). What is holding up the other side of the mod's floor? Another beam? Be safe, G

 

[Build]

Build, the inspection is not for the hole, it is because that is a lame way to connect the floor system together over a bearing beam. The Inspector would be from the Building Department to OK the building for final occupancy. The mess you have would not pass inspection. To back fill an 8' basement without bracing inside as they did is not to the minimum safety code. Without braces, the fresh concrete walls could easily crack from all the dirt (clay) compacted from the bobcat).

Page 3- 1st para.- General: Do not install back fill 4ft. and over until walls anchored to floor [404.1.7] IRC (1838.1) UBC
http://www.codecheck.com/cc/images/CC5thEdSample.pdf

The beam appears to be about a foot in the wrong location. It looks like it's only holding up this side (picture side). What is holding up the other side of the mod's floor? Another beam? Be safe, G

The beam is in the middle and it supports both both sections of the house. I know that much. The angle of the picture makes it hard to tell that.

If a home inspector can't tell us if it is safe to make the holes in the joists then who should we contact?

 

[Aggie67]

To back fill an 8' basement without bracing inside as they did is not to the minimum safety code. Without braces, the fresh concrete walls could easily crack from all the dirt (clay) compacted from the bobcat).

Page 3- 1st para.- General: Do not install back fill 4ft. and over until walls anchored to floor [404.1.7] IRC (1838.1) UBC
http://www.codecheck.com/cc/images/CC5thEdSample.pdf

Good catch.

 

[Build]

Any help on who to contact about the desired holes?

 

[Aggie67]

If a home inspector can't tell us if it is safe to make the holes in the joists then who should we contact?

This is my humble opinion, but I don't think the building inspector will want to bless a hole there if he ever knew the company that manufactured the structure told you to call the inspector for his blessing. I think the inspector will want something from the company saying it's ok to make a hole through the marriage line there. The inspectors in my area wouldn't make that call. (Put it this way, I had to write a letter last week and seal it with my stamp to bless a contractor's idea to go from 1/2"x3.75" wedge anchors to 5/8"x7" chem anchors - obviously a safe bet, but the inspector wanted zero liability.)

I still think that since this is brand new construction, the question has to be answered by the guy that designed and manufactured the structure. The builder may say it's ok, but then he's taking some liability there. As for the gap, I think the inspector might want to weigh in on that: he might say it can stay if you get me a signed and sealed letter from the manufacturer, otherwise I'm not passing it.

 

[Build]

Ok so have an inspector inspect the beam and gap.

As for the hole for the ductwork, forget about it and drop the ductwork down below the beam and back up the other side to get to the trunk.

Does that sound reasonable?

 

[Gary in WA]

No, that will create to much restriction and back pressure in the heating system.

I mentioned inspector because the beam/joist connection is not there. The 2x6's every 3-4' are not normal. Each joist should be toe-nailed to the supporting 2x10, and the rim joists should be toe-nailed every 12" as well. You should have full bearing under the 2x10, at least a 2x8, or whatever the Structural Engineer requires. All this should be nailed together sufficiently to resist earthquakes and normal direct and lateral loading. I seriously doubt what you have would suffice.

The builder should be informed of what his workers did (the 2x6 pieces) and given opportunity to fix same. Perhaps some Simpson strapping or ? as per Structural Engineer's directions, to positive tie the floor joists to the beam. I would want to see the S.E.'s written document as per fix, if a ? is added under the 2x10 flat. It is almost impossible to use nails only after the fact. This should be fixed before the ducting is run as to cut a big hole through both rims would weaken them without the full bearing you are missing. Be safe, G

 

[Wildie]

IMHO, its my thought that the rim joist was required for shipping and installation purposes. Now that its supported the whole distance by the glue/lam, a penetration for the duct work would be no problem.
If this were constructed on site, there would not be a rim joist in this position at all.
However, an inspector won't jeopardize himself by OKing without a signed drawing from an engineer.
I would think that the manufacturer would/should provide the engineering drawing!

 

[Build]

We have an inspector coming on Friday to look over everything. I will call the company and ask about an engineering drawing. That is a good idea.

 

[jogr]

The hole through the rim looks like a big problem right now with the way the rim and joists are supported (or not supported).

It looks to me like the rim is functioning as a beam right now since it is only supported every 4 feet. A 2x8" board laying flat and supported only every 4 ft provides way, way too little load capacity. And see how the joint between two of the flat 2x8s is out about 24 inches from the short 2x6 blocks - that means very little went to essentially zero. So all that load is being carried by the rim that is supported every 4 feet. Now if there is a joint in the rim between those 4 foot supports (and there probably is somewhere) then you compound the problem.

Once the support is fixed so that it is continous and anchored down securely then the hole through the rim joist should be no problem.

The manufacturer/installer should be taking the lead on addressing this. Push them hard. I't should actually be a fairly easy fix of replacing the short blocks with a continous member and applying the correct connectors - but the manufacturer or some other engineer needs to spec it.

 

[Build]

The inspector came yesterday and said the beam and how it was installed is correct. He said that cutting the desired holes for ductwork is not a problem. The joist are only there for transporting the house.

Now for the best tools to cut the hole. I would like to cut as clean of hole as possible. I have read people mention a reciprocating saw but can a person get a nice round hole with one?