Solid core Doors... Different types?

I just ordered and got in about 8 interior thickness solid core doors. (from Lowes) They seem extremely light compared to the ones I have at work that I know to be solid particle board exterior type doors. Now the ones at work are 25 years old, is it possible that the newer doors are filled with something else like foam? I am having a hard time getting any answer from Lowes as to what is in the middle. I am thinking about drilling a 1/4 hole in from the hinge side about 6 inches deep and looking inside. If it is wood I'll just glue a dowell up in the hole. Anyway I made the assumption that solid core meant solid wood product, has anyone run into anything else filled into the solid core doors? I am concerned the doors will be useless for attenuating sound if they are filled with something other than wood or particle board. Thanks, Tom

Does it sound hollow when you knock on the doors?

My solid core doors actually have some kind of green sawdust looking stuff in the middle. I thought they were solid timber but when I drilled ball catch holes the middles are green!!. Very strange indeed. They were heavy though and seem to do an OK job. The seals will be the defining thing anyway. JohnG

There are different types of solid core doors. The main three are solid wood, partical wood, and foam. Solid wood, like if it's a solid oak door, is very expensive. Not necessarily a whole lot better, but a lot more expensive. Partical wood is a much more economical choice. I've seen a few different styles of fill, but the ones I just bought for my studio are filled with a sort of chunky looking saw dust. They're very solid and stop quite a bit of sound. I bought them as solid pieces, not pre-hung and no hole for a door knob (very important in a studio) and they were only $47 a piece at Home Depot. I already have a router and bit for the hinges, so I walked away not spending very much at all. Foam core is more for insulation than sound isolation. Of course 99% of construction guys and about 99.9% of the guys at the stores will tell you the foam is for sound proofing... but we all know how much most people know about sound and foam. :) Those are more for exterior installations, but I'm sure you could find plenty of interior doors with foam on the inside.

SonicClang wrote:

There are different types of solid core doors. The main three are solid wood, partical wood, and foam. Foam core is more for insulation than sound isolation. Of course 99% of construction guys and about 99.9% of the guys at the stores will tell you the foam is for sound proofing... but we all know how much most people know about sound and foam. :) Those are more for exterior installations, but I'm sure you could find plenty of interior doors with foam on the inside.

I am hoping that these are not foam filled, but they are lighter than expected. The doors dont sound hollow but they dont sound dull and dense either. When I ordered them they did not offer any choices , and I was unaware there were solidcore doors other than the particle board type since that is all I've ever seen. I know the seals are most important particularly for those rooms that wont see really loud action, but I want the density I paid for. I paid 90 + bucks a door Contractors price for SOLID CORE, not foam. Arrrrrgh! I am frustrated with these guys. They came when I was at work and I had a crew working on the studio when they arrived. Before I could notice the lightness the frames were installed and the sheetrock trimmed up close and sound caulked all in. (the double sheetrock was allready layed extending into the door opening). I know I can yank the doors off the hinges and replace the slabs, so all is not lost. The doors are hung but not drilled out for any knobs or latches yet. Thanks for you replies, it basically reinforces my concern that these are not right. If I am stuck having to keep these, is there a relativel inexpensive way to add the needed mass, such as screw and glue MDF to the doors? Thanks, Tom

I can tell you that the 36" X 80" doors I just bought, were HEAVY with a capital HEAVY. I had to get my brother to come with me to load them into the van. When I installed them I was alone, and I had a pretty tough time handling them by myself. So you may be right, yours may be foam filled.

Today must be the "Lowes door day". My exterior door arrived today at Lowes have to pick it up now. I feel your pain in regards to asking Lowes (or HD) sales persons about what the inside of a door is made of. They simply do no know, however I patiently sat with my sales guy, he called Jeld-wen doors and we "almost" found out. Lowes did provide me with specs of door for my building permit to make sure it meets wind sheer & energy rating for Florida. I did look at other doors on lowes.com and homedepot.com and the links to manufacturers for specs are not always real links... some are web pages made specifically for that retailer AND/OR if you do find the real manufacturer web site they may not have all the info BUT at least Jeld-wen and some others refer to another site that does have a stock pile of info: http://www.ebuild.com/ I found all the specs on my door on the above link, maybe they have yours too. Good Luck :D Marc

.... AND, I hope you video-ed it all!... sounds like it could have made a great slapstick routine.... :D

SonicClang wrote:

I can tell you that the 36" X 80" doors I just bought, were HEAVY with a capital HEAVY. I had to get my brother to come with me to load them into the van. When I installed them I was alone, and I had a pretty tough time handling them by myself. So you may be right, yours may be foam filled.

Unfortunately I installed them when I was in a huge hurry and I didn't have the camcorder going for that one. :)

Just off the top of my head, I don't know that I've ever seen pre-hung (which it sounds like you got) solid core doors. If I were a bettin' man, I'm thinking they just screwed up and didn't give you what you ordered (and paid for). On the other hand, you could do what I did on 3 of my 6 doors and that's make a "Knightfly sandwich" door. You can search for "doors" and find Steve's post about it. Basically, you take a hollow core door and glue a layer of MDF (I used 3/4" but 1" would probably be better) on each side. You can only screw around the perimeter (because there's nothing to hold the screws in the middle and you don't want to "short out" the isolation by screwing from one MDF sheet into the other. According to Steve's calculations, you even end up with a slightly better door in the process. It's VERY important to note that this won't work if you have double doors (like I have going from my main room to my vocal booth) because you end up with a quad leaf system. As a last point, I paid about $100 for my solid core doors (and I know they're solid because I had to cut them to size so I saw the innards), and the same size hollow core door panels were going for about $25 at Lowes and HD so for what you paid, you should have gotten the real thing. len

len-morgan wrote:

It's VERY important to note that this won't work if you have double doors (like I have going from my main room to my vocal booth) because you end up with a quad leaf system.

Len, this is a mistake....... the manner in which hollow core doors a manufactured - (i.e.: with a cardboard honeycomb interior that's bonded to both surfaces) does not create a 2 leaf assembly - and thus 2 doors can't create a 4 leaf system. The honeycomb is too small to allow the door leafs to act as single units. Sincerely, Rod

Interesting... So the honeycomb bridges the faces, thus the door ends up as one really wimpy mass/leaf -- the point being that each face won't resonante independently... :roll: --Keith :mrgreen:

Rod - my average is dropping like a rock today!!! While I passed on apparently incorrect info, I thought I had pretty good source for it: From this link: http://www.johnlsayers.com/phpBB2/viewtopic.php?t=1662

knightfly wrote:

If you're feeling REALLY constructive, you can get better results with a single door if you use a HOLLOW core door Question Question - (say WHAT!!?!) - yeah, you can make your own mass/air/mass door from a hollow core door by laminating at least 5/8" MDF to both sides,

I'll do a lot more listening now and a little less talking :-) len

Don't feel bad, I thought your post sounded... wel... sound. :)

len-morgan wrote:

Rod - my average is dropping like a rock today!!! While I passed on apparently incorrect info, I thought I had pretty good source for it: From this link: http://www.johnlsayers.com/phpBB2/viewtopic.php?t=1662

knightfly wrote:

If you're feeling REALLY constructive, you can get better results with a single door if you use a HOLLOW core door Question Question - (say WHAT!!?!) - yeah, you can make your own mass/air/mass door from a hollow core door by laminating at least 5/8" MDF to both sides,

I'll do a lot more listening now and a little less talking :-) len

Len, Steve is correct that you can make a decent door using a hollow core door as the base........ but (at the time of that particular post) there was a mistaken thought that this would create a 2 leaf MAM system. Rod

I knew the stock doors were hollow core, these were custom ordered from Lowes, made to order. I took one of the smaller doors and drilled a 3/8ths hole in from the latch edge and found it was filled with a brown fibrous material the looked like sow low density fiberboard. I guess it is technically a solid core door, just not what I had in mind. I'll try them out. since most of the passages are double doored I'll just see how they perform. If I have too I'll go back later and add MDF as necessary, or simply go get new/used slabs at the surplus shop which is probably cheaper athan th $20 some odd bucks for 3/4 MDF. Thanks for your input! Tom

be careful that brown stuff could be asbestos you dont want to go drilling into it.

I'd be surprised if a new door had asbsestos in it. Around here, asbestos has pretty much ceased to be used in building materials since the '70s I think. --Keith :mrgreen:

tmix wrote:

I took one of the smaller doors and drilled a 3/8ths hole in from the latch edge and found it was filled with a brown fibrous material the looked like sow low density fiberboard.

Tom - what you have are doors manufactured by Masonite - with a masonite fill - their version of a solid core door treated for sound isolation in the range of STC (i.e.: just for the range of the human voice) - they won't help you at all with low frequency transmissions. Rod

Rod, What would be your advice? Most of the rooms these doors are on are things like Bathroom, computer/machine rooms and storage closets, but I do have a double door entry to the outside world with one of these behind an exterior metal door, and I have 2 each as entry to the drum booth and vocal booth. Thanks for any input. Tom

sharward wrote:

I'd be surprised if a new door had asbsestos in it. Around here, asbestos has pretty much ceased to be used in building materials since the '70s I think. --Keith :mrgreen:

It's important to point out that, unlike popular thought, asbestos hasn't been banned. A lot of people think that it has been. Just wanted to say that. :)

Not only that, but in certain existing situations where asbestos has been, it is sometimes not recommended to remove it... For example, there has been this recent squak about my neighborhood's elementary school having asbestos flooring tiles in a few areas... But it seems if asbestos tiles are solid and attached, it would be more of a hazard to remove them if there is no other need to (i.e., if there is no remodelling going on, etc.)... Removing them could possibly cause the asbestos to become friable, which WOULD then create a hazard. On the other hand, if the asbestos tiles come off the floor in one piece, there is really not much problem with them (but getting the mastic off the floor -- which can also contain asbestos -- may be more of a problem). K

SonicClang wrote:

It's important to point out that, unlike popular thought, asbestos hasn't been banned. A lot of people think that it has been. Just wanted to say that. :)