Deck Vibration

[Xeryus]

Hi folks, I just moved this from the woodwork forums- hope you can help.

I built a deck of the back of my house but the problem is vibration, if the kids are running around the deck i can feel vibration feeding back into the house, and the same with them running around in the house, deck has some vibration. By vibration i mean you can see say liquid in a cup being disturbed, no too the point of spilling, but more violently then i would expect. So the deck is attacked to a 2 story house i used the houses existing bearers and extended them, the deck is 4 meters by 8 meters and a height of 2meters to 2.4m ( ground clearance)
Is this normal? can it be sorted out and how so?
I can provide more info and photo;s if needed, thanks for your help.

Edit : After some more careful inspecting i think there is some slight swaying/wobble in the deck, next too impossible to notice, but it may being causing the feedback thru the Bearers?

[r3nov8or]

It would be helpful to know the sizes, spacing and spans of you bearers and joists. Since you've joined onto the existing bearers, if the deck construction is at the minimum (but safe) standard, spring in the deck would be noticeable and some of the bounce/spring and resulting vibrations could be transfered to your house bearers.

But 'swaying' is a concern and with the height of 2+ metres you should ensure you have adequate cross bracing from the deck (top of the posts) to the base of your posts.

[ringtail]

Photos and details would be great thanks mate. Any details or photos of any bracing would be good too

[Xeryus]

The bearers are 2.4 meters apart i then placed the joists at 400 apart, the posts are also at 2.4 apart the are treated pine 90x90 mpg12? < not sure on this but it was advised from the timber yard, joists are also mpg10, Bearers are i think of the top of my head 190/80? joists are 150/50.
Joists are screw nailed and straped.
My terminology might not be correct , kind of typing this on the run, i will edit it later when home and measure correctly and get a photo.
Thank you for your replies

[ringtail]

Sweet

[Bloss]

A deck of that height will need bracing - and that means in each plane - triangles provide strength other shapes (squares & rectangles)are inherently unstable. Add some timber or steel strap bracing from top of one post to bottom of adjacent one and vice versa is best, but they can be braced with shorter pieces of timber too. 45 degrees is ideal, but that can be varied to suit the specific structure.