[Monkey Wrench]

Id leave the slope it will help it shed rain.
a mistake was made at some point by the tperson who laid the flooring not only does that look strange, . the end grain is exposed to the weather, that will cause it to draw water into the flooring from the expposed edges, becuase of capillary action.

a way to prevent this capillary action is to end the planks with a plank that runs parallel to the edge of the decking.

looking at the door threshold , it may be original and should slope away from the door by about 4 degrees, it is common for thresholds to be replaced by those who dont really understand how to build a threshold but the bottom of the door should be tapered as well so they fit, when the door closes, the gap closes.
new houses in general do not have a taper int eh bottom of the door and the ledge is often also level, thise are modern building techniques.

i ttakes a little doing to replace a threshold as it runs under the door frame and needs to be cut in a certain shape to be done correctly. quite often a person without knowledge of old doors will be called in to effect a reapair and rather than copying what was there they use a more modern technique.




I noted there is little or a small gap beneath this threshold, maybe the flooring was doubled up at some point.

looking up from underneath may show if there are in fact two layers of flooring, laying two layers will cause capillary action, same happens if one sisters lumber in a wet environment. capillary action defies gravity.

if you have already one layer of flooring it is a easy fix just to put another overtop and ften the person will then alternate the flooring direction as it makes sense to them from a structural point of view.


the house has been there a while , I would not expect things to shift much and yes it may be more unlevel than it began, the general rule of thumb is 1: 48, 1/4" over 3 feet. same as plumbing.

I'd exceed ot to try to keep water out from creeping into the deck , when rain hits the outer edges.

possible to jack the posts and put shims under or change the footings. if its not rotten Id wait. it looks nice.

very common issue is that a crpenter doesn't take into account water shed and builds a porch level, causing the structure to fail when capillary action causes wood to not dry out.

another common issue is failure to allow enough gap, the planks all move across the grain seasonally so they need room to move. it is likely tongue and grrove so thare is no drainage between the planks. If non T and G flooring is used then the gaps may be sufficient ot let the floor dry, wiht T and G flooring there may be gaps but you can't leave that open space that you could with solid planking.


a way to approach the issue and provide dry space is to pull up the flooring, lay new plywood and fiberglass it, then its like an upside down boat keeping water out from the framing.. Id also add "cant strips" along the house and around the support posts. they cause the fiberglass to have a little edge, protecting any water shed to the house and ledger plate area and to prevent water from the deck from rotting the posts below the deck.

obviously fiberglass trends away from the vintage appeal, I did my ( 1924) front porch like that and my back porch which was a later addition. I do like the longevity and the fact it made the space below and the structure very dry. no more painting, no more rot. less historic looking. it is a trade off. dont fibergass over old wood. it will delaminate.

I think that deck rotted and the person who restored it probebly changed the flooring direction but also tried to keep it looking original, If so It could be corrected but Id leave it if its not rotten now, might be ok for years yet.

are there two layers of flooring?

originally I bet there was an inch from the bottom of the threshold to the deck and I think that gap was filled by an additional layer of 3/4 T and G.
it prevented the need for the flooring to be completely removed.

if that outer edge of decking is exposed ot rain it will draw water in several feet and the decking will retain it. if it is decent fir it may last a while ..

if there is a second layer I'd remove the outer edge , cut it away a few inches. lay a plank parallel th the edge, leave a spall gap between. Wood won't wick so much if the endgrain is not exposed to the elements like that,, It looks more professional if one does not see that exposed endgrain from the outside edge.

if water wicks in and stays, that creates rot. if gaps are large enough they break capillary action and allow air in to dry the lumber when it does get wet. likely the unlevelness is helping to some degree, for it to try to shed water.

the issue is that capillary action defies gravity and the builder may often fail to realize that. if the gap is under about 1/16" the water will happily run uphill.

dip the corner of a paper towel in your coffee , then you can watch water run uphill, thats due to capillary action. It defies gravity. it has to do with the surface tension of water.

very important to think about how capillary action will destroy a deck when building one and most can be prevented.

it does have a roof, that shelter is obviously helping deter rot so I don't think the floor looks rotten and it may last a good while yet.

if it aint broke , don't fix it ;-)
i cannot se theroof overhang but when the wind blows the edge of the deck probably draws in water.

when the water hits the posts, it will run down the post, Id look at the framing below the deck in this area and see if maybe there is rot from water collecting as it is basically fed by the posts. there appears to be a bit near the bottom deflecting it somewhat but the posts can cause a concentration of rain water in this area by acting as a conductor basically. obviously the round posts are an important historic detail.

what commonly happens is instead of using large lumber a carpenter will sister lumber together creating a striong beam, that is common in framing a door or window header but there it is dry.

the problem wiht sistering near the edges of a porch, is it allows that small gap to retain water that is drawn in by capillary action.

when it cannot dry easily, rot takes hold. I cant see below the deck but Id look sot see if any lumber is sistered together that may have been added in an atempt at restoration in the past.

great big fir beams are more expensive today than they once were.. To save money you can sister modern lumber sizes. it's not uncommon to see pressure treated lumber sistered.