Info on joists

Wikey

Posted here previously with regard to sound from next door neighbours. Just wondering if anyone can explain to me how joists work between semi-d's. Some people have mentioned that we may be sharing joists with neighbour. Does this mean that the same pieces of wood supporting our floor is also supporting theirs? Other people have said that the joists may be touching, not sure I totally understand this either.

Thanks for any info,

Wikey

teepee

The answer is no you are not sharing the same joist , the proplem is there was a practice that was used on party walls up to about 5 years ago where the joists abutted in to the wall a saddle bracket was used to support the joist from both sides , this meant that one peice of metal is share by both houses dus the sound traveling throught . This practice has know been band , instead the hanger is bolted to the wall with raw bolts . Have a look at the link and you will see what i mean .
Teepee .
http://www.batmetalwork.com/product_joist.html

Wikey

Thanks Teepee. Diagram really helps. House is about 30 yrs old. I'm amazed one piece of metal can transfer such an amount of noise.

Mellor

teepee wrote: »

The answer is no you are not sharing the same joist , the proplem is there was a practice that was used on party walls up to about 5 years ago where the joists abutted in to the wall a saddle bracket was used to support the joist from both sides ,

That stopped being permitted a lot more than 5 years ago. The double joists hangers are used internally. And it wasn't stopped due to sound, it was fire.


OP, there was a time when joists carried through over the party wall. But that should have stopped by 1980. But then again, without building regs in place, people may have tried to get away with it (unlikely in living room). More likely is that both were built into the wall (also banned now) and it's a weak point.

Wikey

Mellor wrote: »

That stopped being permitted a lot more than 5 years ago. The double joists hangers are used internally. And it wasn't stopped due to sound, it was fire.


OP, there was a time when joists carried through over the party wall. But that should have stopped by 1980. But then again, without building regs in place, people may have tried to get away with it (unlikely in living room). More likely is that both were built into the wall (also banned now) and it's a weak point.

Thanks Mellor, is there any solution to the noise problem, so? We've sound proofed the parti wall but didn't go near the floors. House was built around the 80's, semi d with living rooms and bedrooms sharing the parti wall. Front doors and stairs are on at the far side of each house, yet we still hear them going up and down the stairs.

Poor Uncle Tom

Just a thought,

Check your attic, if the house was built in the early '80's then the party wall may not have been carried up to the underside of the roof, it may finish at ceiling level, using the attic space as a sound box.

Wikey

Poor Uncle Tom wrote: »

Just a thought,

Check your attic, if the house was built in the early '80's then the party wall may not have been carried up to the underside of the roof, it may finish at ceiling level, using the attic space as a sound box.

Nope, parti wall does go up to the roof. Looking on the internet, are we just hearing flanking noises? Is that were the sound is being transferred on to our joists and bouncing around between the floor and ceiling, i.e between the joists?

muffler

Whats the party wall like? Is it single block, cavity block, cavity wall,???

Wikey

I think it's just regular 4 x 9 blocks with no cavity on the party wall. It's a standard 3 bed semi-d,100m sq, built around 1980's. We'd the party wall insulated with a product called Calibel,a plasterboard with glasswool on it. Has made a bit of a difference but impact noises are still bad so reckon something going on with joists.

muffler

Strange one alright. Have you actually checked to see if the joists run into the party wall?

In almost all semi-d's the joists would run from front to back but my sister had a 30+ year old house near Tallaght and the front wall began to move a bit. Having got an engineer to inspect it she discovered the joists were running from gable wall to party wall.

Nothing really surprises me.

Get a local chippy to have a look for you. It will entail lifting the carpet only but if it shows that the joists are built into the party wall there is a chance that they may overlap with your neighbours joists at this point.

Wikey

muffler wrote: »

Strange one alright. Have you actually checked to see if the joists run into the party wall?

In almost all semi-d's the joists would run from front to back but my sister had a 30+ year old house near Tallaght and the front wall began to move a bit. Having got an engineer to inspect it she discovered the joists were running from gable wall to party wall.

Nothing really surprises me.

Get a local chippy to have a look for you. It will entail lifting the carpet only but if it shows that the joists are built into the party wall there is a chance that they may overlap with your neighbours joists at this point.

Cheers Muffler, appreciate all the info. When we were getting carpets put down the floor boards were running from front wall to back and just checked under bath and joists under it are running from the party wall to gable. As I type folks next door are going up stairs. It's a different type of noise to when we go up are own stairs but it's practically just as loud.....stairs are on opposite sides of each house!

My head is absolute wrecked to be honest. Feel like we have little to no privacy while paying a mortgage of half a mill.

Anybody got any solutions to this

Thanks to all who have read or posted a response.

Mellor

I think my previous guess was pretty accurate based on some of the latest info. The joists are likely built in and close proximity to each other.