Multiple cracks appearing after part of roof beam removed!!

[Nathan76]

Hi All,

I hope I am in the right section.....

I live in a 3 bed mid terrace 1950s ex council house (the roofing style is in the second pic and have recently had our loft hatch moved from what will be our baby room into the landing. Simple for someone who knows what they are doing.....and they seemed to.
A carpenter has blocked off our old hatch and put a new one in, a pretty good job on the face of it. However, to install the new hatch they have cut through a large beam (marked 2) (I believe they called it a pearling?!?) the house has 4 of these running the entire width of the loft. I will try to attach a picture.....where they have removed this beam the new loft hatch sits nicely and they have put a slightly smaller beam (marked 1) next to it screwed to the "joists?" (the 600mm apart beam that the celiing attaches to the underside of?) I was worried about this at the time but was assured this would be ok.
Hatch was fitted about 4 weeks ago. Over the last 3 years we have had a number of ceilings skimmed and all have been fine until the day before yesterday! We now have small cracks appearing in the ceilings of all three bedrooms, the landing and the upstairs toilet.

The cracks are very narrow, some would say hairline, but they have all appeared in the last 48 hours or so.......

I'm not panicking but I would like some advice as to whether this sounds like I need to check with a structural engineer or similar?

Can anyone put my mind at ease please? Any help gladly appreciated.

Many thanks

Nathan

 

[bernardgreen]

this sounds like I need to check with a structural engineer or similar?

Yes.... you do need to check this with a structural engineer.

The beam that has been cut is almost certainly a tie beam that prevents the base of the rafters moving outwards and sliding off the tops of the walls.

It is a structural member of the roof structure and should not have been cut.

 

[tony1851]

The timber that has been cut is a binder (not a purlin - they are higher up).

It will be providing some support to the ceiling joists to prevent them from sagging. The ceiling joists also prevent the roof from spreading, but if only 2 or 3 are cut, and adequately tied, it shouldn't be a big problem.

Hard to say without knowing what compensatory work (if any) the joiner did.

 

[vinn]

tony1851 is on to it.
OP, ignore the hysterical ignorance above his post - no cause for alarm or the attendance of a SE needed.

Whoever cut in the opening for the hatch has not trimmed ie. supported the Binder cuts. The flat 2"x ( No 1 ) might be taking up some of the weight but the cuts should be supported.
Nor, so it seems, have they trimmed the ceiling joists with doubled trimming joists supporting the trimmers.
google pics of joist trimming and what I'm saying might become more clear to you?

When cutting a hatch opening of any kind in joists or rafters you must support the cut members with a surround of same size (section) timbers - aka trimming.
If the opening is not supported the joists will sag slightly, & perhaps crack the plaster finish below.
The actual custom hatch is fixed between the trimming timbers.

 

[John D v2.0]

Yes as said above it's probably a binder for stopping the ceiling sagging but since it's classed as structural work then an SE should really have designed it. The joists should be stopping the roof spreading so hopefully you're fine on that account.
Get the person on the phone and ask how they designed it, and if the answer isn't useful then you might need to look at repairing it with another tradesmen to a proper design.

 

[John D v2.0]

Sorry replied before I saw vinns, yes agreed don't panic, but I'm not sure you can just trim around gaps in binders because theye are probably not enough binders to trim to? Joists and rafters are usually close enough spaced.
Interested to hear how to deal with this as we want to make an opening and the advice from the architect was don't touch the binders. We haven't yet got the design from the SE, but will ask him if it's possible.

 

[vinn]

There are four binders in the loft in question.

Its good practice to avoid cutting the Binder(s) or similar framing details, esp. if its a Truss roof.
Hatches are most often cut in existing loft floors to make the access more safe or practical - or to provide a location for loft ladders.
Are you saying that you are using an Architect and a SE to advise on whats essentially a simple carpentry job?

 

[vinn]

OP.
Has your custom hatch been fixed with hangers or brackets - how is it secured to the surrounding joists?

 

[John D v2.0]

There are four binders in the loft in question.

Its good practice to avoid cutting the Binder(s) or similar framing details, esp. if its a Truss roof.
Hatches are most often cut in existing loft floors to make the access more safe or practical - or to provide a location for loft ladders.
Are you saying that you are using an Architect and a SE to advise on whats essentially a simple carpentry job?

No sorry i didn't want to hijack too much, actually we're having massive alterations to upstairs, downstairs, and the roof, including making a light well. As such the SE is designing the roof including the light well, which we would like as large as practical. Hence why I know a little, but I am interested in learning more!

 

[Nathan76]

Thank tony and bernard. The first picture shows a beam up and right of the loft hatch. This is the only compensatory work done.
With what Tony says Bernard do you agree?

Thanks again.

 

[Nathan76]

Hello all. Thank you for all the replies. I will have a look again tonight when i get home to see about the trimming joists etc. and have a look to see how the hatch is fixed to the joists. If only i had seen them fit skirting before they did my loft hatch.......
Admittedly they haven't finished it yet......

 

[bernardgreen]

What is at the ends of the beam that has been cut ?

Are the ends attached to base of rafters to form triangle as in this sketch ?

The red beam, refered to as a tie beam, stops the bottoms of the brown rafters moving apart.

Tony is right in saying that ceiling joists are often used to act as tie beams but that is not always the way it is done.

Many roof have trusses which do not use joists as the tie beams

 

[vinn]

What more rubbish is this - why are you continuing to advise nonsense out of your limitless ignorance.
Stay away from advising/misleading people when you dont know what you are talking about.
You, literally, dont have a clue about what you are looking at.

You appear to be a DIY'er who misunderstands the information he googles up - you have definitely never worked a day in the building trades. Stick with your "Agony aunt" activities.

Keep up such unacceptable posts & you will eventually cause some trusting reader to have an expensive, & possibly harmful accident.

 

[JohnD]

From the picture and the description, I thought it was a beam running from gable to gable, in which case cutting it would not cause the rafters to spread.

Is that right?

 

[bernardgreen]

What more rubbish is this - why are you continuing to advise nonsense out of your limitless ignorance.

I suggested that the OP consult a structural engineer. This would result in an inspection of the roof structure in the loft and determination if the cut beam has compromised the roof structure. To say there is no problem with cutting that beam when you have not inspected the structure is more dangerous.

In 1980 I built a house ( DIY ) which had roof trusses using tie beams ( long before Google was started ) I still have the architect's drawings ( Walter Segal ) and most of the calculations used in the design of the frame and trusses.