as the title says...
we will be installing an ftx unit in the attic and would like to bring down exhaust air into the basement. We will be opening the floors on the living level anyway, but the duct will need to run across the joists. Is this okay? Can the joists be reinforced sufficiently? There are square vent ducts in plastic, which require less notching of the joists (about 5.5 cm instead of the diameter of a round duct). The joists are about 20 cm. Or do we need to rethink?
Will the joists be weakened (despite possible reinforcement) to the extent that we won't be able to place a stove on the joists?
The house is about 7 meters with an iron beam in the middle, so about 3.5 meters of the joists will be affected.
I posted the question in ventilation before but got the suggestion that it is mainly a structural issue.
we will be installing an ftx unit in the attic and would like to bring down exhaust air into the basement. We will be opening the floors on the living level anyway, but the duct will need to run across the joists. Is this okay? Can the joists be reinforced sufficiently? There are square vent ducts in plastic, which require less notching of the joists (about 5.5 cm instead of the diameter of a round duct). The joists are about 20 cm. Or do we need to rethink?
Will the joists be weakened (despite possible reinforcement) to the extent that we won't be able to place a stove on the joists?
The house is about 7 meters with an iron beam in the middle, so about 3.5 meters of the joists will be affected.
I posted the question in ventilation before but got the suggestion that it is mainly a structural issue.
Contact a structural engineer for an on-site inspection.
Try to think again. Is there really no other way to route the pipe?
If not, the above applies, contact a designer to calculate your specific case.
If not, the above applies, contact a designer to calculate your specific case.
We chose to keep the supply and exhaust air ducts visible in the basement when they run along the house (instead of sawing/drilling through the joists of the intermediate floor, where the ducts run across the house, we have placed them in the intermediate floor.
I have a few meters of 100mm spiro ducting running through my intermediate floor at one place. This was done in connection with new construction, so I never notched the floor joists but drilled holes and inserted the ducts from the side.
At the places where I drilled these holes, I screwed and glued a one meter 45x45 both above and below the hole.
At the places where I drilled these holes, I screwed and glued a one meter 45x45 both above and below the hole.
I would think more than once before running a ventilation duct through the joist framework, and avoid it as much as possible. But if you still have to do it, make the hole as close to the joist's attachments as possible, where the load is minimal on the joist. Also, try to reinforce the joist, for example by notching and screwing plywood on both sides of the joist. Also, consult with an engineer.
Even if you might not break the joist, you definitely risk causing instability and deflections.
Even if you might not break the joist, you definitely risk causing instability and deflections.
I discussed the same issue with our engineer before our addition of a second floor. We will have 45x220 beams in the intermediate floor, and at a couple of locations, we will need to run spiro across the flooring. We also have an iron beam supporting in the middle with a span of about 4 m on the floor between the beam and the wall.
His response was that if you do not make "too many" penetrations across the beams, drill 100-125 mm holes centered in the beams, and then reinforce with 45x45 screwed on each side of the beams' top and bottom edges, it should be fine. It was not a question of notching the beams, but centered holes were what "applied."
"Too many" was not fully defined, but 3-4 was not a problem. If more were required, he would calculate it.
Regarding a stove, we are also planning to have a fireplace in a lounge on the upper floor in the long term, and the engineer has designed beams at c300, i.e., doubled compared to normal to withstand the extra weight. We discussed a fireplace and not a tiled stove or a stove with tiles, so it is not a heavy installation, and just there, we will not pass through with spiro. If you intend to have a stove in the place where you need to pass through the floor with ventilation ducts, I would definitely recommend talking to an engineer to calculate it.
His response was that if you do not make "too many" penetrations across the beams, drill 100-125 mm holes centered in the beams, and then reinforce with 45x45 screwed on each side of the beams' top and bottom edges, it should be fine. It was not a question of notching the beams, but centered holes were what "applied."
"Too many" was not fully defined, but 3-4 was not a problem. If more were required, he would calculate it.
Regarding a stove, we are also planning to have a fireplace in a lounge on the upper floor in the long term, and the engineer has designed beams at c300, i.e., doubled compared to normal to withstand the extra weight. We discussed a fireplace and not a tiled stove or a stove with tiles, so it is not a heavy installation, and just there, we will not pass through with spiro. If you intend to have a stove in the place where you need to pass through the floor with ventilation ducts, I would definitely recommend talking to an engineer to calculate it.
Thank you for all the answers! We were thinking of consulting a structural engineer; we're not the type to start such major renovations after "just" asking here, but I assume he would need to know the exact dimensions of the joists and the distance between the studs (meaning he would need to open the floor), and it feels like we're not there yet. We're working on a 50 sqm extension and therefore need to order a ventilation plan ASAP. I just wanted to check here if there was a chance. From the tester, it sounds like there is, so we'll go for it; otherwise, we'll have to ask them to redraw the plan later.
some "new" info. Needed to open the floor in the bathroom to check how the water came in. Then we see that the joists consist of a thick beam and then a 45 on top. They have then cut this, i.e., made a break in it, where the water crosses. Does this change the load-bearing capacity? i.e., if we lay plastic pipes, do we only need to carve about a cm out of the main beam?