JOIST/BEAM SUPPORT - Main beam in Cellar?

Question

JOIST/BEAM SUPPORT - Main beam in Cellar?

Sorry about lack of detail. I didnt expect such good answers on this subject from such good people so this is a repost. Your all good people...

Do i only need one joist/beam support hanger to support a Oak beam to the CELLAR wall as a fail safe incase it breaks at the weak end by the wall? The beam is 4.1" wide x 6" (100x150mm)
If need be, does anyone know which hanger type i should use for the job? IE bolt the hanger to the wall and support the main beam if need be. The beam is nearly 200 years and im worried it might snap one day!

SUMMARY:
The 15ft Main oak beam, is nearly 200 years old and apparently still strong, HOWEVER the one end which is in the old stone wall seems to be showing a TINY bit of play when i wobble it. It also has a small crack at the end part. This naturally makes me Paranoid as this beam is supporting a whole front room under the joists which are also 200 years old. As this is the ONLY wooden Cellar Beam supporting ALL of the joists of the front room and upper floors, it seems to have a tiny bit of play when i wobble it, as well of a small crack, so naturally im PARANOID/WORRIED the front room floor might collapse destroying everything i own as gas pipe is also under it! (Play as in when i grab it with both hands and shake it, it has a tiny bit of play. Im worried it might be rotton behind the wall which i CANT see.)
I do have house insurance but thats not the point as allegedly prevention is better than cure. I cant as of yet afford a builder to inspect the situation. The beam is 15ft long by 4"wide and 6" high. But if this snaps at the weak end by the wall, my whole family is a gonna and thats obviously not good. Ive heard that Acro props might do the job and/or builing a brick/block support post might fix it temporarily? If this is true the How/Why!?

If you'd like a pic of this beam then i can email you one. My email is [e-mail] or click or copy and paste this link https://plus.google.com/u/0/

Many thanks for your help and input in to this matter.

Additional Details:-
This is the main beam as in the pics in this link: https://plus.google.com/u/0/ that runs across the whole ceiling under the floor joists and in to next doors wall. Yes it is 4x6" which is not of todays standards but was then in the Victorian erea.
The beam also supports the wooden cellar stairs which lead to the cellar down the wall.
Yes i think i'll have to fix a joist hanger and a prop underneath as a fail safe..? I cant take the beam out as it supports the side of the cellar stairs. The internal walls of the house are made of Wattle n Daub lashings and Rat trap brick work.

Answer 1

i have answered this question before ...not in a million years did a builder fit a 6x4 beam with a 15 foot span 200 years ago ...it cetainly would not be there now ..it would have been in two halves ..victorian builders rarely underestimated load bearing dimensions ..your is a mile out ..the golden rule for a normal floor joist is ..half the span plus1 ..so a 15 ft span would require a 9x2 joist ..@ 16" centres ....and you will have no chance of any movement by hand ..so fit a acrow prop each end and one in middle ..now ring for a builder to inspect ..

Answer 2

Add a post under the main beam on that end just to be sure, but frankly if it's been there for 200 years, it's not going anywhere now. It probably dried out in place, that wobble has been around longer than you have. Still, if you're scared about it, fix it so it can't go anywhere. It won't break, but might slip off the end of the wall maybe. Old oak, you won't be driving nails or screws into it, you probably can't even drill into it without going through lots of bits. Old oak like that gets extremely tough. I tried to cut some 200 year old oak flooring once, a circular saw, a jig saw, and even a chain saw wouldn't touch it. Took a custom made special chainsaw blade to cut the duct holes in it, and even then wasn't easy. The special titanium tipped blade was worn out after cutting 8 small holes.

Answer 3

It's hard to picture the situation. But if I was really concerned I would put posts under the beam.