Is this dry rot?

[Donnie]

Random bits of this around my garage roof like this...

is it something to worry about? Cheers. 

[Macpherson]

HI, it's unlikely to be dry rot with exposed timbers like that, dry rot requires poorly ventilated highly humid conditions, that looks more like staining from a leaky roof either past or present.

 

Stick a knife into the suspect timber to see if it's soft in any way.

[Squaredy]

9 hours ago, JDon said:

Random bits of this around my garage roof like this...

is it something to worry about? Cheers. 

Clearly there has been a leak, so this needs to be repaired if not already  done.  Then secondly as has been said check for soft parts in those beams.  
 

Remember that dry rot and wet rot both need moisture, so as long as the leak is only historic then no new rot will take place.  Just find out if the timber is still strong.  I would use a hammer to hit the beams.  If they are sound you will leave slight marks.  If rotten they will get severely damaged by the hammer.

[Guest Gimlet]

On 07/04/2023 at 22:49, JDon said:

Random bits of this around my garage roof like this...

is it something to worry about? Cheers. 

A roof covered with floorboards? Is there a room above the garage, like a bathroom?

[petercb]

could be mycelium on bottom of one of rafters?

[spudulike]

A friend had a leaky bath and many years after, I was doing a bit of work on their ceiling and the joists under the leak had turned in to something resembling a crunchie chocolate bar.

Even if the timber is good I would treat the timbers in something that will kill off any spores otherwise, you may get issues in the future.

Your log water content meter will help tell you how dry the wood is. a hammer and screwdriver will prove the hardness of the wood.