Slight dip in roof

Hi , was just looking for abit of advice -
We are just buying a new house and the surveyor has advised us to get checked a slight dip in the rear roof … the house was constructed about 1960 and I think its the original roof -

I have a roofer coming round to have a look who says alot of the time its just the way the weight of the roof has lay and alot of the time there is nothing to worry about and the roof is sound …

Is a dip often nothing to worry about ??

Any help would be appreciated


You would have to look in attic to see the extent of reason its dipping, if its just a dip you would tear off old sheathing in that area and build back up level, don’t leave like some roofers who just roof over bowed sheathing, it will look more nice if leveled out.

Ok cheers –

Is this a big problem though you think ?

Im told alot of older houses have this quirk and it can be left without problem ?

It depends if the dip is between two rafters/trusses or between eave and ridge. And of course the amount of deflection. Between the rafters is a minor sheathing repair, between eave and ridge is MUCH more involved. Many older homes were “stick” built with lumber sizes that would not pass code now. However this type of dip is usually more of a cosmetic problem. More details and pics would help us steer you in the right direction.

This is the way to repair a slight dip in roof

These dips are notorious and are nationwide.Mostly in your older homes.I have seen them on homes from the 1890’s up to the 90’s and maybe newer.

Lots of things contribute to this structural anomaly.

Foundation settling,multiple layers exceeding the structures intended max weight load,multiple layers over shake roofs are also notorious for having truss/support issues…Improper bracing.,twisted or busted trusses maybe due to the home having had a tree or large branch fall on it.

It is not out of the normal for roof structures to be different measurements from rake to rake and in the center.

Meaning on a gable roof the rake on the left might be 20’ and the right might be 19’/10"
but the center of the roof is 19’.6".,so the center would be sunken on the ridge 6" from center rake to rake.

I have also seen this with dormers too.Steep roofs also have this problem.Generally from out dated structure reinforcement techniques.These occur mostly in the center of the roof.(Field)

These dips are generally simple to correct.I usually find the source of the problem then correct that.Then I will reset/reinforce the truss.Not finding the original culprit for the problem might have the same thing happen in the future.

Do I think it is a huge structural issue?.,Not a clue.It will depend on what actually caused the dip in the first place.But I can say.,the house is still standing. :badgrin:

That depends, if it is a dip in the sheeting between two trusses, then usually it is not a structural problem, just a cosmetic issue. These are usually caused by the sheeting being 3/8" plywood that has sagged over time and can be fixed by installing a new piece of sheeting or you could put a piece of 2x4 between the trusses to level out the sheet of wood (called “blocking”).

If it is a dip like A1SoCalroofer illustrated, then yes it is structural and should be fixed.

Can you advise if I should be concerned about the dips/humps in this supposedly 10 year old roof on a home I’m considering buying…

I respect your opinion!
Much appreciated!

Yes and that is not slight.

Wood Sheeting popping up in the middle,
It will be leaking soon if it isnt already.
Then about 4 feet below is the result of a bad
leak or a broken truss.
If it was a leak, it would surely be exposed on the inside.
I am strongly leaning toward a broken truss.

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My roof is 3 years old and a small dip(3’x3’) has just occurred down about 6-8’ from eave on side of roof hear back of roof. The installer wants to charge me $1,200 to tear off 1 square replace the sheeting and put new peel and stick/plywood then shinges.
He has agreed if when he tears off, there’s a gap between two sheetings then his roofing guys did it and he will not charge but if not then I should pay. I have a 10 year warranty on workmanship so even if its a bad sheet of plywood, shouldn’t he do it for free?
What do you think; I am a senior citizen and not knowledgeable about roofs.

Post a pic so we can see how bad it is.

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If this is on a new house, the roofer usually does not install the sheathing.

If this is an old house, the roofer only replaces wood that is damaged or rotten at the time of replacement.

If he went over a sheet of plywood and it was fastened down and was not loose, then it pops three years later, that is not his fault. The roof deck will typically last through at least 3 roofs and usually a lot more. You can’t expect him to be responsible for 30 or more year old fasteners failing when he put the roof on 3 years ago and they were working then.

If when he did the roof he replaced sheathing and it is one of the boards he replaced, then it is generous of him to offer to fix it. The roof warranty you have for material and workmanship if it is from the shingle manufacturer does not cover the roof deck. Even if it was replaced with the roof. If you have a 10 year installer warranty from this company then it may cover it, depending on the language. If this had happened within a year of him replacing deck and one of his boards popped loose, he would need to fix it for sure.

Never done a tear off without re-nailing the deck. “Re-nail deck as necessary” is on the proposal immediately after “replace any bad deck at $$$ per square”. Deck nails get pulled during tear off. Doesn’t anyone take pride in their work anymore? Even on new construction, a roofer knows if the deck is nailed or not. You can feel it vibrate.

In our area, the trade market for exteriors has long shifted toward an independent subtrade model where earnings are based on what is “installed” and not what is “prepped or fixed” properly. The roofing market has long since become commoditized and in doing so has also followed the same path as all other industries/services who have fallen victim to the same high output trap. Where you once had your local bookstores or hardware store where expertise was the value imbedded into the price, you now have online distribution and box stores where quality and service are burdensome costs nobody is willing to shoulder at the risk of paying more. It’s a complicated new paradigm to shift because it costs money and the baby boomers are the last generation likely to pay for this. Their influence and numbers are quickly diminishing.

Of course you should if you can feel it vibrate or move. Around here that isn’t a common line item though.

My point was that in three years on an old building, what was once fastened down can come loose. Even if you re-nail as necessary, it may not have been necessary then, but the deck might come loose later.

Let me make this clear, I did not come here with any expectations or to complain or act assinine and I am willing to pay to get the roof right so when the next major hurricane hits, we have a chance of keeping the roof. The house is well maintained for last 20+ years.
This house is in florida, survived 3 major hurricanes in past 15 years, the latest re-roof is the 2nd complete reroof(the 1st reroof was not good) and is 3 years old(after cat.4 Irma) and roofer replaced plywood where necessary at no cost. Its a peel and stick on plywood followed by owens corning trudefinition duration shingle.

I hope you didn’t take what I said as implying you were here to complain or act asinine. I was just explaining how things work where I am at. Some of the posters here are from Florida and can give you a better idea of local customs.

Salesmen running around contracting jobs and then trying to find the cheapest DGAF clowns to do the work. Did I get that right.


More or less you are correct. Homeowners who are also lured in by the slickest website proclaiming 73 years of “combined” experience unaware the company, which looks great, has a “combined staff” of 14 individuals. This industry will always have salesmen as it will installers. Alternately to your remark though, the same thing can be said about installers who through setting up a website, now feel they are skilled enough to deal with consumers when they can hardly balance their own finances, maintain insurance or uphold a warranty.

Once upon a time it seemed better but was also likely less complex than what it is now. One’s “word” meant something and could be verified by talking to others who were free to speak openly of their experience. Not so much anymore when most of society has the attention span of a housefly and has done everything possible to avoid human contact.