I bought my house in 2015 and the survey mentioned dry rot in the porch. The porch was all wooden and at parts barely attached to the house. We’ve just had the porch replaced and a PVC one built (yes we left the dry rot one there for years). I haven’t looked into dry rot before until now, as we appear to be having problems with the new porch as one wall (the most exposed and damaged one from the last porch) is soaking with the rain getting in behind the plaster. I never saw the cobweb like stuff (though I guess it did have cobwebs that I just assumed were dust). But I definitely never saw the mushroom stage of dry rot with the old porch. However now my partner has looked at the top of our bay window in the front room (on the side of the porch which is leaking) and thinks there’s dry rot there as it looks a bit mouldy and has little yellow bits. Is there a spray I can use on that small area to treat it/see if it clears up? We’re not sure if this problem in the porch is blown rendering, so we were considering that option, however now I’m concerned it may be a big dry rot issue. Though would dry rot cause the new porch’s plastered wall inside to get wet, and get progressively worse every time it rains?