I just need help with containment procedures and some proofreading if you'd be so kind.
Lets not get too hasty. This is going to get murdered as is regardless of proofreading. Its just plain sloppy. Not necessarily a bad idea, but really sloppily delivered.
Check your wording. Much of this scp is not technical in nature, and you are forgetting a technical article is not going to use the term elements or miasma unless referring to an old theory.
Drop the alternate dimension portal in the back door. It just doesn't make sense to tack onto your article, and delivery wise its awful. Make the interior of the house the "alternate dimension" or at least the interior is suffering from a bleeding effect.
Instead of having a "miasma vent" have the interior convert diseases into a gas form. Have one of the previous owners die of smallpox, and make the crisis related to these weaponized diseases leaking and infecting others. You could even have the Foundation researching how to "bottle" these gases for weaponized delivery.
Finally I have looked over your entry closely and created this pastebin with some of my suggestions.