1998 Addition Sheathing Stains

[Jon mackay]

This is either a slab on grade or inaccessible crawl addition, really could not tell.
It appears to have been built in 1998.

There are soffit vents and a ridge vent but all the sheathing is stained.
No bathroom or kitchen in the addition, just a room that is currently being used as a band practice room (drums, microphone, etc.)

All I could think of was moisture below but the floor (carpet) was dry.

Any other thoughts on the cause?

[Garry Sorrells]

These pictures look familiar. Have you posted them before?

Did notice on some of the pictures the nails through sheathing are rusted on top half of picture. Which would indicate excessive moisture.

What type of ridge vent does roof have?

Often rooms used for musical instruments have humidifiers or have self contained controls to maintain heat and humidify levels at a static point.

The more expensive the instruments the better the climate controls.

[John Kogel]

They are using the attic for storage, etc, but the roof sheathing is uninsulated. They are probably allowing heated air from downstairs up into the space too much, too often. Pull-down stairs are bad for leaking warm air up into the attic. I tell people to build an insulated box with an insulated lid over the hole.

You must determine if the house is on a crawlspace or slab. Post a pic here. What year built?

[Jon mackay]

You must determine if the house is on a crawlspace or slab. Post a pic here. What year built?

Further investigation on foundation type is forthcoming.

The year built 1998

[Jon mackay]

These pictures look familiar. Have you posted them before?

Did notice on some of the pictures the nails through sheathing are rusted on top half of picture. Which would indicate excessive moisture.

What type of ridge vent does roof have?

Often rooms used for musical instruments have humidifiers or have self contained controls to maintain heat and humidify levels at a static point.

The more expensive the instruments the better the climate controls.

No, I have not posted these before, similar ones I'm sure.

Excessive moisture for sure but why the buildup? Perhaps the ventilation needs to be increased..

The ridge vent is a metal type (no shingles).

I did not notice any type of humidification system.

[John Kogel]

Excessive moisture for sure but why the buildup? Perhaps the ventilation needs to be increased..

The ridge vent is a metal type (no shingles).

Is this the house with the woodstove in the living room? There has possibly been a lot of warm moist air leaking up from the living space into the cool attic. Poor circulation of heated air downstairs, so they throw on another log, more heat in the living room, bedroom is still cold, etc. This woodstove lifestyle worked in the old drafty houses but in a modern house, you need to keep a heat source on in every room to be comfortable.

I see light all along the soffit area, and with a ridge vent, I would think the attic ventilation is OK. Stop the leakage from downstairs.

[Jon mackay]

Is this the house with the wood stove in the living room?

Same house but sealed off from the wood stove area.

I am thinking that if there is in fact a crawl space, it is likely very wet based on the other low areas.
I will investigate that tomorrow..