Lowered Ceiling, but are joists, hangers/bolts up to load??


Postby minty77 » Tue Aug 02, 2011 9:19 pm

Calling all DIYers.....I may well be worrying about nothing but felt it best to check and apologies if this is in the wrong forum area, it's not so much about the sound proofing but more the structual side.

I am a novice DIY guy and basically have been forced into creating an independent ceiling due to a very noisy and obnoxious neighbour (both airborne & impact noise) so I set about planning this and as you will see by the photo's I have progressed through but I have started to doubt myself on the load capability of the joists and the hangers/bolts that I've spec'd for.

I don't make it a habbit of hanging off joists but I am 82Kg and can hang from one of the newly installed joists without any fixture movement, noise etc (just a little beam flex) but despite that I'm still doubting myself with structural integrity concerns.

Room/House details
60's build end terrace house (converted to maisonette's c20 years ago)
Lounge is 11.83ft x 11.91ft (Joists span the 11.83ft gap)
Typical 1/2 inch masonary and then red brick for each of the four walls

I'll just step you through what's gone on up to this point (just in case there is relevance)

Original ceiling removed & original deep joists exposed
High density acoustic wool packed between joists
5 sheets of 15mm Gyproc soundbloc screwed to original joists (41kg per sheet)
2mm thick membrane covering added to each plasterboard sheet before raising to ceiling and fixing in place (between sheet and joist)

New Ceiling specs

(9) Joist Beams - 50mm x 100mm x 3.6m C16 Kiln Dried Wood (Jewson although looks like it's imported from Germany by the markings)

(18) Masonary Joist hangers 50mm x 135mm

(36) M10 x 16mm Shield Anchors torqued to 15ftlb per bolt (2 bolts on each hanger which have secured extremely well on every hole)

My concern is have I got my (novice) calculations right and created something which is structurally sound from a load perspective, it may only be dead load but with 5 sheets of 15mm soundbloc plasterboard (205Kg total) and a skimmed ceiling (60 - 80Kg) it could be weighing a considerable amount by the time I'm done so I have to ask the question.... are the beams going to hold and are the walls/bolt fixtures up to the job?

I appreciate any advice on this project, green light to carry on or stop and think again. I have pictures but couldn't work out how the heck to upload them!

Thanks

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minty77
Posts: 3
Joined: Tue Aug 02, 2011 7:26 am

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Postby minty77 » Wed Aug 03, 2011 9:14 am

minty77 wrote:Calling all DIYers.....I may well be worrying about nothing but felt it best to check and apologies if this is in the wrong forum area, it's not so much about the sound proofing but more the structual side.

I am a novice DIY guy and basically have been forced into creating an independent ceiling due to a very noisy and obnoxious neighbour (both airborne & impact noise) so I set about planning this and as you will see by the photo's I have progressed through but I have started to doubt myself on the load capability of the joists and the hangers/bolts that I've spec'd for.

I don't make it a habbit of hanging off joists but I am 82Kg and can hang from one of the newly installed joists without any fixture movement, noise etc (just a little beam flex) but despite that I'm still doubting myself with structural integrity concerns.

Room/House details
60's build end terrace house (converted to maisonette's c20 years ago)
Lounge is 11.83ft x 11.91ft (Joists span the 11.83ft gap)
Typical 1/2 inch masonary and then red brick for each of the four walls

I'll just step you through what's gone on up to this point (just in case there is relevance)

Original ceiling removed & original deep joists exposed
High density acoustic wool packed between joists
5 sheets of 15mm Gyproc soundbloc screwed to original joists (41kg per sheet)
2mm thick membrane covering added to each plasterboard sheet before raising to ceiling and fixing in place (between sheet and joist)

New Ceiling specs

Joists set at 400mm centres

(9) Joist Beams - 50mm x 100mm x 3.6m C16 Kiln Dried Wood (Jewson although looks like it's imported from Germany by the markings)

(18) Masonary Joist hangers 50mm x 135mm

(36) M10 x 16mm Shield Anchors torqued to 15ftlb per bolt (2 bolts on each hanger which have secured extremely well on every hole)

My concern is have I got my (novice) calculations right and created something which is structurally sound from a load perspective, it may only be dead load but with 5 sheets of 15mm soundbloc plasterboard (205Kg total) and a skimmed ceiling (60 - 80Kg) it could be weighing a considerable amount by the time I'm done so I have to ask the question.... are the beams going to hold and are the walls/bolt fixtures up to the job?

I appreciate any advice on this project, green light to carry on or stop and think again.

Thanks

[Image

[Image

[Image

[Image
minty77
Posts: 3
Joined: Tue Aug 02, 2011 7:26 am


Postby minty77 » Wed Aug 03, 2011 11:45 am

minty77 wrote:Calling all DIYers.....I may well be worrying about nothing but felt it best to check and apologies if this is in the wrong forum area, it's not so much about the sound proofing but more the structual side.

I am a novice DIY guy and basically have been forced into creating an independent ceiling due to a very noisy and obnoxious neighbour (both airborne & impact noise) so I set about planning this and as you will see by the photo's I have progressed through but I have started to doubt myself on the load capability of the joists and the hangers/bolts that I've spec'd for.

I don't make it a habbit of hanging off joists but I am 82Kg and can hang from one of the newly installed joists without any fixture movement, noise etc (just a little beam flex) but despite that I'm still doubting myself with structural integrity concerns.

Room/House details
60's build end terrace house (converted to maisonette's c20 years ago)
Lounge is 11.83ft x 11.91ft (Joists span the 11.83ft gap)
Typical 1/2 inch masonary and then red brick for each of the four walls

I'll just step you through what's gone on up to this point (just in case there is relevance)

Original ceiling removed & original deep joists exposed
High density acoustic wool packed between joists
5 sheets of 15mm Gyproc soundbloc screwed to original joists (41kg per sheet)
2mm thick membrane covering added to each plasterboard sheet before raising to ceiling and fixing in place (between sheet and joist)

New Ceiling specs

(9) Joist Beams - 50mm x 100mm x 3.6m C16 Kiln Dried Wood (Jewson although looks like it's imported from Germany by the markings)

(18) Masonary Joist hangers 50mm x 135mm

(36) M10 x 16mm Shield Anchors torqued to 15ftlb per bolt (2 bolts on each hanger which have secured extremely well on every hole)

My concern is have I got my (novice) calculations right and created something which is structurally sound from a load perspective, it may only be dead load but with 5 sheets of 15mm soundbloc plasterboard (205Kg total) and a skimmed ceiling (60 - 80Kg) it could be weighing a considerable amount by the time I'm done so I have to ask the question.... are the beams going to hold and are the walls/bolt fixtures up to the job?

I appreciate any advice on this project, green light to carry on or stop and think again. I have pictures but couldn't work out how the heck to upload them!

Thanks

[Image

[Image

[Image

[Image


UPDATE - I had a structural engineer take a look at my specs and images and he has given the green light stating that the structure/timber that I have created would be fine and would be 85-90% of maxium load which is fine. I have decided to put another layer of 15mm soundbloc sheet up against original joists and do my own joists with a layer of 12.5mm soundbloc (not 15mm) to keep weight down and be extra safe.
minty77
Posts: 3
Joined: Tue Aug 02, 2011 7:26 am


Postby Brickworkz » Wed Aug 03, 2011 6:55 pm

The only thing I would add is cross bracing in between the new joists to help prevent movement and fixings to the original joists to help prevent sagging.
Brickworkz
Posts: 18
Joined: Wed Aug 03, 2011 8:22 am


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