RFZ based control room in an A frame attic.

[Bassmankr]

John, glad to see you moved up some of the collar beams however they need more than just two nails in each end (something a code inspecter would catch). Basically they are only as good as the shear value of the fastners you have in their ends as the force on them is pulling the sides of the roof outward. You could also nail a one foot 2x to the center of the collar beam (on the same side as the roof joists), then add two 2x 45 degree struts up from that same center board, tied into the roof joists. You can do the same trick down low with the existing knee wall 2x if you plan on keeping them. Triangles always stiffen a structure. Since you are not including a bathroom I would build some storage space in the area you have to box out between the vent pipe and chimney.

[johndykstra]

Hey bassmankr,

thanks for joining us.

When we took the collar ties down, they had been fastened with a single nail. I figured two are better than one right? Granted, they aren't the same gauge as the old one. Do you think some lag bolts would do the trick? I hesitate with the added struts up above, as we are leaving these exposed in the CR. That would be a lot of drywall notching, not to mention it would severely hinder the ceiling fan. In the lounge it wouldn't be a huge deal, as that area the collar ties are covered. Also, remember there is a second added collar tie up near the peak for a drywall nailer. I know it's up pretty high where it isn't providing a ton of shearing resistance, but it's gotta be helping.

As far as the closet in the lounge, we are avoiding that for the same reason we are avoiding the bathroom. Either of those two features automatically designate the area from a recreational space, to a bedroom. Lots of code requirements at that point. The lounge is laid out pretty well. I haven't included the plans here because they only recently became finalized. Alongside the chimney will be a bar that wraps around in a "u" shape to meet the vent stack... I'm gonna draw it. Check the design thread later.

[Bassmankr]

Just add two long screws to the two nails you already have. Do a piliot hole for them so you don't have to worry about spliting the wood ends. That should beef it up and keep it simple. Lag bolts are overkill and you don't have much wood member to wood member contact area to begin with. One original nail huh . . LOL and people wonder why we need building inspectors. Having a bit more time to look at your plans, the lounge layout looks fine but cut it down to two maybe three bar stools as that's about all the room you will have. They make under counter beverage fridges you can pick up for under $150 (you don't really want to haul a full fridge up those stairs do you LOL) and just doing the u-shaped counter from the fireplace over to a wrap of the vent pipe would work. Build some under counter cabinets next to the fridge and into the knee wall. I'd leave the brick chimney exposed in the lounge at least since it looks nice. I doubt if boxing off the knee wall next to the stairs and having an access door to it would count as a closet for a bedroom since it would only be maybe 2'-6" high but still would be a nice area to stash recording stuff when not in use. Just a rough guess but for that size control room you probably have to many absorbers drawn for the ceiling. It might end up being too dead. If you have an additional second higher up collar beam (leaving the lower one exposed like you planed you can still have a flat ceiling with a bit more space above it for insulation. I'm guessing from the pics that the bottom of the exposed tie beams are at 7'-6" up from the floor and you could put the bottom of the smaller higher up tie beams at 9' up from the floor. That would make drywalling a bit easier and might help some with the acoustics. You would still have room for absorber panels and ceiling fan but not really take that many cubic feet of volume away. That upper triangle you form would be used as a bass trap either way, so by having a small flat dryway ceiling up there at least you won't be killing off too much high end. Maybe stuff some rockwool in that space instead of light fluffy fibergalss batts so it works better as a bass trap. If I get some time I'll pencil a couple quick sketches for you.

[johndykstra]

Hey bassmankr.

check on the screws.

check on the under-counter cabinets (too lazy to draw them)

the fridge wasn't supposed to look full size, rather the smallest fridge/freeze combo I can find (gotta have some frozen pizzas for the Pizaz)

the rest of the lounge is really not to scale, so bar stools and such were just for the concept. We are going to sheath the chimney, it's not as nice looking as you might expect. Plus the way the back wall is being designed, the wrap around the chimney is a needed sheathing layer for the minimum isolation we are going to get.

The area behind the knee walls in the lounge, I am going to have access panels on there. Good place for empty boxes and such.


Regarding the trapping drawn in the control room, understood. Essentially I was drawing in trapping anywhere I could vision it being. How much actually gets executed in the end will only be decided with measurements.

The secondary collar tie in the control room is already installed. There is 7" of vertical clearance between the ridge beam and the top of the collar tie. Basically, I left myself enough room for a 5" flex duct for exhaust. Maximize room volume, minimize parallel floor and ceiling, and maximize potential trap depth.

[Bassmankr]

Looks like you've got it handled. If you can get at least 4" of rockwool above the drywall flat ceiling formed by the upper/2nd collar tie beam and then run that 5" flex duct in the triangle left above it you should have a nice bass absorber hidden in the structure and then add broadband absorbers around the room to taste. Remember to keep feeding us pics of the progress.

[Syncamorea]

(deleted to re-purify the thread it contaminated)

[johndykstra]

The blocking that composes the trim around the collar ties should provide excellent lateral stiffness. Really no way the nails and addition of screws can work loose with the trim in place.

In regards to resonance, I do have concerns. The first three exposed collar ties will be covered by my reflectors. (I've decided to omit the first collar tie you see in the above photo. It's functionality should be covered by the speaker soffit wall.) Plenty of opportunity to add stringers between the collar ties without a visual impact. It's an added bonus that these first three are also closest to the speakers, so the ties that are most prone to resonance I can deal with without aesthetic penalty. If measurements show that I need to add stringers to all of the collar ties, so be it.

[johndykstra]

Demo work sure is dusty


We've got some cleaning to do. Also, this one Hvac supply will be sealed off


starting from the rafter ties which are level, I measured down to find the location for the header of the knee walls. I then plumed the first and last studs of the wall, and ran a string along the face at the top and bottom to ensure my wall was being built true. There was a variance of ~2" in the height of these studs along the entire house's length (most occurring in the lounge thankfully) given the age of the house, this is why I built the wall in place, and not simply construct and stand it in.


I have the knee walls unfinished at the front of the control room. I will finish these walls only after the soffit wall is done.. this way the soffit wall can be continuous.


this is the knee wall for the right wall of the control room, and it extends into the lounge. Although it looks and is continuous, there is a break where the wall that splits the two rooms will go. The back wall of the control room will extend from eve to eve, and all the way to the peak. Here you can also see that we are hap-hazzardly laying the new flooring down, until we can get under there in one step and: sister in floor joists, run electrical, and insulate


doing our best to keep building materials off the floor to make finishing the floor and electrical all the easier


this is flooring material removed from the lounge. all of the flooring from the control room side has already been moved off site.


this is all that remains to remove before we get to the next step. that corner bit in the distance.

[Bassmankr]

Hey you are making progress! At least you are using the right tool for the right job (that case of PBR) LOL. Are you still planning to add diagonal cross braces back into the roof in the knee wall space?

[johndykstra]

Originally Posted by Bassmankr

Hey you are making progress! At least you are using the right tool for the right job (that case of PBR) LOL. Are you still planning to add diagonal cross braces back into the roof in the knee wall space?

yes. That will be on the second, not yet constructed smaller knee walls