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Do i need structural engineer advice prior joists blocking?

I want to strengthen my floor as it is bouncy and it shakes a bit when walking.
I'd like to put blocks between joists (known as joists blocking).

Can I do it myself?
Or do I need a structural engineer to advise how many blocks and at what distance etc.. prior doing this?

Since I would be touching structural parts (joists) I am concerned I should not do anything by common sense but rather seek struct eng advise first.

What would you recommend to do joists blocking properly?

Please answer all the questions above

Thanks in advance for your clarifications

4 Answers from MyBuilder Carpenters & Joiners

Best Answer

I would strongly recommend structural engineer but to cut the cost down you can get a very experienced builder which it would be less costly than structural engineer to give you advise how to do it than you can do it yourself,
Without looking at the floor is very limited advise I can give,but if your flooring is very bouncy, apart from blocks)noggins you might need to put whole new full length of joists to doubly them up with the old joists would give more strength as old joist could be weakened, rotten or even invisible cracks.

I hope that answers your questions
Good luck



Answered 15th Jul 2019

If its a floor other than the ground floor the joists sectional dimension should be increased alternatively glulam or I beams could be installed. If its the ground floor it could be the timber wall plate supporting the joists may be rotton, check any air bricks are installed correctly and the air flow below the flooring isn't compromised, is the damp coarse damaged?
I agree an experienced builder would be a cost effective solution to identify and rectify any defects rather than the costly survey of a structural engineer.


Answered 16th Jul 2019

It’s difficult to answer without seeing the floor. If it’s just a case of lifting the flooring and adding in noggins where needed then this is relatively simple. If you are going to start cutting joists then you either need a competent carpenter/builder with liability insurance or you can get in a structural engineer ( the expensive option)


Answered 19th Jul 2019

You need to expose the beams and check their suitability for the span, also the spacing between beams(centres), have any walls been removed underneath. How long is the span?

It's a straight forward job but should have been done when beams were placed originally.
You don't need a structural engineer. You can do it yourself. Use blocks of same cross section as joists and fit tightly and fix securely.
If you're not cutting through joists or altering joists layout then a structural engineer would be unnecessary.
If you first expose the joists and they are compromised/rotten/split you can replace like for like.


Answered 31st Jul 2019

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