Rising damp interior- best method to treat?

Water can get in just about any where. See if you can get a thermal scanner...water is usually cooler than the surroundings and on most scanners it showed up blue...between my parents place and the 3 houses I’ve had..it’s been a crack in the foundation, a leak around a pipe going up thru the roof, a runnoff issue from the roof, and a river flooding. Broken shingles, malfunctioning windows. Dehumidifiers help quite a bit. You have to find where the water is getting in.

I googled "Thermal Scanners" and they come in a variety of prices. But if you are having moisture problems, it would be well worth the $99 to $499 prices I saw.

Some houses do not have wide eves and rain gets in near the foundation. Make sure your gutters are working too!!

https://www.google.com/search?q=thermal+scanner&rlz=1C1GGRV_enUS751US751&oq=thermal+scanner&aqs=chrome..69i57j0l5.3439j0j4&sourceid=chrome&ie=UTF-8

It sounds like you sealed your attic up and No Ventilation in attic so moisture is being Forced, raised inside the house are you in a high humidity area ? to find out buy a inexpensive electronic thermometer that reads humidity level, that can tell you if its' high. Do you windows sweat in house? that will tell you , open a window or door on house at each end of home just 1/8" to help venting , is your Dryer Vent plugged or disconnected

Do you have a crawl space is their moisture in crawl space, is their a vapor barrier on the bare ground under house, do you cook,boil, or steam in the house? that will do it, Ventilate your HOUSE You your self can raise humidity. Call HVAC. company they can help you.

This article should help you out! http://www.diydoctor.org.uk/projects/rising-damp.htm